2. STRUCTURE & FUNCTIONS IN LIVING ORGANISMS

Question 2

2.1 cells contain a number of o_________

Answer 2

organelles

Question 3

2.1 organelles are

Answer 3

structures that carry out specific processes the cell needs to survive

Question 4

2.1 tissues are

Answer 4

groups of similar cells

that work together to carry out the same function

Question 5

2.1 an example of tissue in humans is

Answer 5

muscle tissue

Question 6

2.1 organs are made up of

Answer 6

several different tissues

working together to carry out a more complex function

Question 7

2.1 an example of an organ in a human is

Answer 7

the heart

(muscle is one of the tissues making up the heart)

Question 8

2.1 organ systems are made up of

Answer 8

several different organs working together to carry out a complex function essential to life

e.g. circulating blood around the body

Question 9

2.1 organelle ->

Answer 9

cell

Question 10

2.1 cell ->

Answer 10

tissue

Question 11

2.1 tissue ->

Answer 11

organ

Question 12

2.1 organ ->

Answer 12

organ system

Question 13

2.1 organ system ->

Answer 13

organism

Question 14

2.1 organelle ->

c , t , o , o & o

Answer 14

cell, tissue, organ, organ system & organism

Question 15

2.2 cells are separated from their surrounding environment by

Answer 15

a cell membrane

Question 16

2.2 within the cell membrane is the

Answer 16

cytoplasm

Question 17

2.2 eukaryotic cells have … contained within their cytoplasm

Answer 17

organelles

Question 18

2.2 organelles are

Answer 18

where specific processes take place within the cell

Question 19

2.2 what is in the cytoplasm of a eukaryotic cell

Answer 19

nucleus, mitochondria & ribosomes

Question 20

2.2 plant cells contain the following additional structures

Answer 20

cell wall, chloroplasts & a vacuole

Question 21

2.3 function of the nucleus

Answer 21

contains genetic material in chromosomes
controls cell division

Question 22

2.3 function of the cytoplasm

Answer 22

supports cell structure
site of many chemical reactions
contains water and many solutes
jelly-like substance

Question 23

2.3 function of the cell membrane

Answer 23

holds the cell together
controls substances entering and leaving the cell

Question 24

2.3 function of the cell wall

Answer 24

gives the cell extra support and defines its shape

Question 25

2.3 function of the mitochondria

Answer 25

site of aerobic respiration providing energy for the cell

Question 26

2.3 function of the chloroplasts

Answer 26

site of photosynthesis - provides food for plants chlorophyll pigment absorbs light energy

Question 27

2.3 function of the ribosomes

Answer 27

the site of protein synthesis

Question 28

2.3 function of the vacuole

Answer 28

contains cell sap used for storage helps support the shape of the cell

Question 29

2.4 how many structures does a plant cell have

Answer 29

8

Question 30

2.4 how many structures does an animal cell have

Answer 30

5

Question 31

2.4 in addition to the structures an animal cell has, a plant cell also has

Answer 31

chloroplasts, a (cellulose) cell wall and a vacuole

Question 32

2.4 what does an animal cell have

Answer 32

a nucleus, cell membrane, mitochondria, ribosomes and a cytoplasm

Question 33

2.4 what does a plant cell have

Answer 33

a nucleus, cell membrane, mitochondria, ribosomes, cytoplasm, chloroplasts, cell wall and a vacuole

Question 34

2.5B what is cell differentiation

Answer 34

the process by which a cell changes to become specialised

Question 35

2.5B what happens when a cell differentiates

Answer 35

the cells develop the structure & characteristics needed to carry out their functions

Question 36

2.5B when does cell differentiation occur

Answer 36

as an organism develops

Question 37

2.5B give examples of cell differentiation to form specialised cells

Answer 37

nerve cells, red blood cells, root hair cells & palisade mesophyll cells

Question 38

2.6B advantages of stem cells in medicine

Answer 38

- can treat a wide variety of diseases - organs develop from a patient's own stem cells which reduces risk of organ rejection & wait from a donor - stem cell technology can repair damaged organs by growing new tissue from stem cells

Question 39

2.6B disadvantages of stem cells in medicine

Answer 39

- stem cells cultured in a lab could be infected with a virus that could transmit to a patient - risk of cultured stem cells accumulating mutations that can lead to cancer developing - a low number of stem cell donors

Question 40

2.7 the chemical elements present in carbohydrates

Answer 40

carbon, hydrogen and oxygen (C,H,O)

Question 41

2.7 the chemical elements present in proteins

Answer 41

carbon, hydrogen, oxygen and nitrogen (C,H,O,N)

Question 42

2.7 the chemical elements present in lipids (fats&oils)

Answer 42

carbon, hydrogen and oxygen (C,H,O)

Question 43

2.8 starch and glycogen is from

Answer 43

simple sugars

Question 44

2.8 protein is from

Answer 44

amino acids

Question 45

2.8 lipids are from

Answer 45

fatty acids and glycerol

Question 46

2.8 a monosaccharide is a ...

Answer 46

simple sugar like glucose

Question 47

2.8 a disaccharide is made when

Answer 47

two monosaccharides join together e.g. maltose = glucose & glucose sucrose = glucose & fructose

Question 48

2.8 a polysaccharide is formed when

Answer 48

lots of monosaccharides join together

Question 49

2.8 polysaccharides starch, glycogen or cellulose are all formed when

Answer 49

lots of glucose molecules join together

Question 50

2.8 most fats (lipids) in the body are made up of

Answer 50

triglycerides

Question 51

2.8 lipids basic unit is

Answer 51

one glycerol molecule chemically bonded to three fatty acid chains

Question 52

2.8 proteins are formed from

Answer 52

long chains of amino acids

Question 53

2.8 when amino acids are joined together

Answer 53

a protein is formed

Question 54

2.9 what is the test for starch?

Answer 54

iodine solution

Question 55

2.9 explain the test for starch

Answer 55

1. place food sample on a spotting tile 2. add a few drops of iodine solution to the sample 3. blue - black colour indicates starch

Question 56

2.9 what is the test for glucose / reducing sugars?

Answer 56

benedicts solution

Question 57

2.9 explain the test for glucose / reducing sugars?

Answer 57

1. place food sample in a boiling tube 2. add benedict’s solution to the sample of food in solution 3. place in a water bath at 80*c for 5 minutes 4. a change from blue to brick red if present (if green, yellow or orange means less sugar present)

Question 58

2.9 what is the test for protein?

Answer 58

biuret test

Question 59

2.9 explain the test for protein

Answer 59

1. place food sample in a boiling tube 2. add enough biuret solution for colour to be pale blue 3. if protein is present colour will change to mauve / purple

Question 60

2.9 what is the test for lipids?

Answer 60

emulsion test

Question 61

2.9 explain the test for lipids?

Answer 61

1. place food sample in a test tube 2. add small amount of ethanol and shake to dissolve any lipid in the alcohol. 3. add equal volume of water 4. cloudy white colour (emulsion will form) indication presence of lipid

Question 62

2.9 benedicts solution is used to test for

Answer 62

reducing sugars (glucose)

Question 63

2.9 benedicts solution colour change

Answer 63

blue to brick red

Question 64

2.9 how do I remember benedicts solution

Answer 64

christmas sugar

Question 65

2.9 iodine is used to test for

Answer 65

starch

Question 66

2.9 iodine solution colour change

Answer 66

orange to blue-black

Question 67

2.9 how do I remember iodine

Answer 67

bumblebee

Question 68

2.9 biuret is used to test for

Answer 68

protein

Question 69

2.9 biuret solution colour change

Answer 69

(light)blue to pale purple

Question 70

2.9 how do I remember biuret

Answer 70

snowflakes (et) proTEin biurET

Question 71

2.9 emulsion is used to test for

Answer 71

lipids

Question 72

2.9 emulsion colour change

Answer 72

colourless to a cloudy white emulsion

Question 73

2.9 how do I remember emulsion

Answer 73

snowing

Question 74

2.10 enzymes are biological

Answer 74

catalysts

Question 75

2.10 a catalyst is a ........

Answer 75

chemical which increases the rate of a reaction without being used up itself in the reaction

Question 76

2.10 the theory for understanding how enzymes work is the

Answer 76

lock and key theory

Question 77

2.10 what is the lock and key theory

Answer 77

the substrate and enzyme collide, the substrate binds to the active site of the enzyme, (the reaction occurs by an alternative pathway with a lower activation energy) once the reaction occurs, the products don't fit - so they are released, the enzyme is free to catalyse the next reaction

Question 78

2.10 the active site has a particular shape which is ... to the shape of the substrates

Answer 78

complementary

Question 79

2.10 because the shape of the active site is complementary to that of the substrates, this means

Answer 79

each enzyme can only catalyse one reaction

Question 80

2.11 as temperature increases the enzyme & substrate have more

Answer 80

kinetic energy so they move faster and there are more successful collisions

Question 81

2.11 high temperatures and changes of pH cause the shape

Answer 81

to change

Question 82

2.11 when the shape changes we say this is

Answer 82

the protein being denatured

Question 83

2.11 when the active site changes shape it is no longer

Answer 83

complementary to the substrate

Question 84

2.12 practical for investigating effect of temperature on enzymes

Answer 84

place spots of iodine into each dip of a spotting tile add 5cm^3 of starch suspension into a boiling tube w/ a syringe with a different syringe add 5cm^3 of amylase solution into another tube fill a beaker w/ water at 20*C & place both boiling tubes inside for 5 minutes pour amylase solution into the starch suspension leaving it in the water bath take a sample w/ pipette & add a drop to the iodine solution in the spotting tile record colour change of the solution in the tile repeat every 30 seconds for 10 minutes until the iodine solution remains orange indicating the starch is used up repeat the experiment with the water bath at diff temps between 20*C & 60*C

Question 85

2.13 what is the optimum pH for most enzymes

Answer 85

7

Question 86

2.13 which enzymes have a lower pH than 7

Answer 86

those produced in acidic conditions e.g. the stomach - pH 2

Question 87

2.13 which enzymes have a higher pH than 7

Answer 87

those produced in alkaline conditions e.g. the duodenum - pH 8/9

Question 88

2.13 what happens if the pH is too high or too low

Answer 88

the bonds that hold the amino acid chain together can be disrupted / destroyed this changes the shape of the active site so the substrate can no longer fit into it this reduces the rate of activity moving too far away from the pH - the enzyme will denature

Question 89

2.14B practical investigating how enzyme activity can be affected by changes in pH

Answer 89

add a drop of iodine to each well of a spotting tile use a syringe to place 2cm^3 of amylase into a test tube add 1cm^3 of buffer solution (at pH2) to the same test tube using a syringe in another test tube add 2cm^3 of starch solution pour the starch solution into the amylase and buffer solution start a stopwatch whilst mixing the solution using a pipette every 10 seconds transfer a droplet of the solution to a new well of iodine solution which should turn blue black repeat every 10 seconds until the iodine solution stops turning blue-black meaning the amylase has broken down all the starch record the time taken for reaction to be completed repeat the investigation with buffers at different pH values from pH3 - pH7

Question 90

2.14B practical amylase is an enzyme that breaks down

Answer 90

starch into maltose

Question 91

2.14B practical what does it mean when the iodine solution remains orange - brown

Answer 91

that all the starch has broken down

Question 92

2.14B practical what will this investigation show

Answer 92

at the optimum pH the iodine stopped turning blue-black within the shortest amount of time

Question 93

2.14B practical why does the iodine remain orange in the shortest amount of time

Answer 93

because the enzyme is working at its fastest / optimum rate and has digested all of the starch

Question 94

2.14B practical what will happen at a higher or lower pH

Answer 94

the iodine will take longer to stop turning blue-black

Question 95

2.14B practical what is a control variable

Answer 95

the starch and amylase solutions should be placed in a water bath at the optimum temperature before being used

Question 96

2.14B practical name one tool that can be used to measure the progress of the reaction more accurately

Answer 96

using a colorimeter

Question 97

2.14B practical CORMS

Answer 97

C - changing the pH of the environment O - not relevant - no organism R - repeat several times to ensure reliability M - measure time taken for iodine to stop turning blue-black S - control the concentration & volume of the amylase, iodine and starch solution

Question 98

2.15 definition of diffusion

Answer 98

the random movement of particles from an area of higher concentration to an area of lower concentration

Question 99

2.15 definition of osmosis

Answer 99

the net diffusion of free water molecules from an area of high water concentration to an area of low water concentration across a partially permeable membrane

Question 100

2.15 osmosis in cell: what is: solution outside cell has same water potential as inside cell - no net movement

Answer 100

isotonic solution (animal = normal) (plant = flaccid)

Question 101

2.15 osmosis in cell: what is: solution outside cell has higher water potential then inside cell - net movement of free water molecules into cell

Answer 101

hypotonic solution (animal = lysed) (plant = turgid)

Question 102

2.15 osmosis in cell: what is: solution outside cell has lower water potential then inside cell - net movement of free water molecules out of cell

Answer 102

hypertonic solution (animal = shrivelled) (plant = plasmolysed)

Question 103

2.15 definition of active transport

Answer 103

movement of molecules from an area of low concentration to an area of high concentration using ATP

Question 104

2.16 the four main factors that affect the rate of movement

Answer 104

surface area to volume ratio, distance, temperature and concentration gradient

Question 105

2.16 why is a larger surface area a good thing

Answer 105

it quickens the rate at which substances can move across its surface

Question 106

2.16 example of large surface area

Answer 106

highly folded surface of the small intestine increases its surface area

Question 107

2.16 why is a shorter distance a good thing

Answer 107

the smaller the distance molecules have to travel, the faster the transport will occur

Question 108

2.16 example of short diffusion distance

Answer 108

alveoli walls are one cell thick - rate of diffusion across them is as fast as possible

Question 109

2.16 why is higher temperature a good thing

Answer 109

the higher the temperature, the faster molecules move as they have more energy

Question 110

2.16 how is higher temp a good thing

Answer 110

because there are more collisions against the cell membrane and therefore a faster rate of movement across them

Question 111

2.16 why is a greater difference in a concentration gradient a good thing

Answer 111

the greater the difference in concentration on either side of the membrane, the faster movement across it will occur

Question 112

2.16 how is a greater difference in a concentration gradient a good thing

Answer 112

because the on the side with the higher concentration, more random collisions against the membrane will occur

Question 113

2.17 practical: investigating diffusion

Answer 113

coloured agar is made from indicators coloured agar is cut into required dimensions calculate the surface area, SA:V R and volume and record it cubes placed in boiling tubes of different solutions (same volume of it) ^^^ e.g. dilute hydrochloric acid measurements taken of time for cube to completely change colour of indicator can draw a graph of rate of diffusion (rate of colour change) changes with surface area : volume ratio of agar cubes

Question 114

2.17 practical: investigating osmosis

Answer 114

prepare a range of sucrose (sugar) solutions ranging from 0 Mol/dm3 (distilled water) to 1 mol/dm3 set up 6 labelled test tubes with 10cm3 of each of the sucrose solutions using the knife, cork borer and ruler, cut 6 equally-sized cylinders of potato blot each one with a paper towel and weigh on the balance put 1 piece into each concentration of sucrose solution after 4 hours, remove them, blot with paper towels and reweigh them

Question 115

2.18 process of photosynthesis

Answer 115

energy from sunlight is absorbed by chlorophyll, a green pigment found inside chloroplasts green plants use this energy to make the carbohydrate glucose from the raw materials carbon dioxide and water at the same time, oxygen is made and released as a waste product

Question 116

2.19 word and balanced chemical equations for photosynthesis

Answer 116

carbon dioxide + water -> glucose + oxygen 6CO2 + 6H2O -> C6H12O6 + 6O2

Question 117

2.20 how does varying temperature affect the rate of photosynthesis

Answer 117

it affects how much kinetic energy the particles have so affects the speed at which carbon dioxide and water move more successful collisions (too high temp can denature enzymes that control the process of photosynthesis)

Question 118

2.20 how does varying light intensity affect the rate of photosynthesis

Answer 118

the intensity of the light available to the plant will affect the amount of energy that it has to carry out photosynthesis the more light a plant receives, the faster the rate of photosynthesis

Question 119

2.20 how does varying carbon dioxide concentration affect the rate of photosynthesis

Answer 119

carbon dioxide is one of the raw materials required for photosynthesis this means the more carbon dioxide that is present, the faster the reaction can occur

Question 120

2.21 structure of waxy cuticle

Answer 120

protective layer on top of the leaf prevents water from evaporating

Question 121

2.21 structure of upper epidermis

Answer 121

thin and transparent to allow light to enter palisade mesophyll layer underneath

Question 122

2.21 structure of palisade mesophyll

Answer 122

column shaped cells tightly packed with chloroplasts to absorb more light maximising photosynthesis

Question 123

2.21 structure of spongy mesophyll

Answer 123

internal air spaces which increase surface area to volume ratio for the diffusion of gases (mainly carbon dioxide)

Question 124

2.21 structure of lower epidermis

Answer 124

contains guard cells and stomata

Question 125

2.21 structure of guard cell

Answer 125

absorbs and loses water to open and close stomata to allow carbon dioxide to diffuse in oxygen to diffuse out

Question 126

2.21 structure of stomata

Answer 126

where gas exchange takes place opens during day closes during night evaporation of water takes place here found in much greater concentration on underside of leaf to reduce water loss (in most plants)

Question 127

2.21 structure of vascular bundle

Answer 127

contains xylem and phloem to transport substances to and from the leaf

Question 128

2.21 structure of xylem

Answer 128

transports water into leaf for mesophyll cells to use in photosynthesis and for transpiration from stomata

Question 129

2.21 structure of phloem

Answer 129

transports sucrose and amino acids around the plant

Question 130

2.21 what are all the 10 leaf structures

Answer 130

waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis, guard cell, stomata, vascular bundle, xylem and phloem

Question 131

2.21 adaptation of large surface area (leaf)

Answer 131

increases surface area for the diffusion of carbon dioxide and absorption of light for photosynthesis

Question 132

2.21 adaptation of being thin

Answer 132

allows carbon dioxide to diffuse to palisade mesophyll cells quickly

Question 133

2.21 adaptation of chlorophyll

Answer 133

absorbs light energy so that photosynthesis can take place

Question 134

2.21 adaptation of network of veins

Answer 134

allows the transport of water to the cells of the leaf and carbohydrates from the leaf for photosynthesis (water for photosynthesis) (carbohydrates - product of photosynthesis)

Question 135

2.21 adaptation of stomata

Answer 135

allows carbon dioxide to diffuse into the leaf and oxygen to diffuse out

Question 136

2.21 adaptation of epidermis being thin and transparent

Answer 136

allows more light to reach the palisade cells

Question 137

2.21 adaptation of thin cuticle made of wax

Answer 137

to protect the leaf without blocking sunlight

Question 138

2.21 adaptation of palisade cell layer at top of leaf

Answer 138

maximises the absorption of light as it will hit chloroplasts in the cells directly

Question 139

2.21 adaptation of spongy layer

Answer 139

air spaces allow carbon dioxide to diffuse through the leaf increasing surface area

Question 140

2.21 adaptation of vascular bundles

Answer 140

thick cell walls of the tissue in the bundles help to support the stem and leaf

Question 141

2.21 specialised leaf for photosynthesis: large surface area and thin

Answer 141

to maximise absorption of sunlight and increases number of stomata so carbon dioxide can diffuse faster

Question 142

2.21 specialised leaf for photosynthesis: upper epidermis

Answer 142

transparent allowing light to penetrate to the mesophyll

Question 143

2.21 specialised leaf for photosynthesis: palisade cells

Answer 143

long thin and tightly packed w large numbers of chloroplasts main site of photosynthesis

Question 144

2.21 specialised leaf for photosynthesis: stomata

Answer 144

allows gases to diffuse into air spaces of the leaf - short diffusion distance for carbon dioxide

Question 145

2.21 specialised leaf for photosynthesis: xylem transporting water

Answer 145

water that's absorbed in the roots into the leaves so short distance for water to diffuse into cells

Question 146

2.21 specialised leaf for photosynthesis: phloem vessels

Answer 146

phloem vessels transport sugars made in photosynthesis to other parts of plant

Question 147

2.22 plants requires what for growth

Answer 147

mineral ions

Question 148

2.22 chlorophyll requires what to be made

Answer 148

magnesium ions

Question 149

2.22 amino acids require what to be made (so proteins & nucleic acids - DNA & RNA)

Answer 149

nitrate ions

Question 150

2.23 practical: investigate photosynthesis

Answer 150

take a bundle of shoots of a water plant submerge them in a beaker of water underneath an upturned funnel fill a boiling tube with water and place it over the end of the funnel as oxygen is produced, the bubbles of gas will collect in the boiling tube and displace the water show that the gas collected is oxygen by relighting a glowing splint

Question 151

2.23 practical: investigating production of starch & photosynthesis&light

Answer 151

de-starch the plant by placing it in a dark cupboard for 24 hours (this ensures that any starch already present in the leaves will be used up) partially cover a leaf of the plant with aluminium foil and place the plant in sunlight for a day remove the covered leaf and test for starch using iodine: drop the leaf in boiling water (kills the tissue and breaks down the cell walls) transfer the leaf into hot ethanol in a boiling tube for 5-10 minutes (removes the chlorophyll so colour changes from iodine are more clear) rinse the leaf in cold water to soften the leaf tissue spread the leaf out on a white tile and cover it with iodine solution the entire leaf will turn blue-black as photosynthesis is occurring in all areas of the leaf proving light is necessary for photosynthesis and production of starch

Question 152

2.23 practical: CORMS evaluation on light & photosynthesis

Answer 152

C - We are changing whether there is light or no light O - The leaves will be taken from the same plant or same species, age and size of the plant R - We will repeat the investigation several times to ensure our results are reliable M1 - We will observe the colour change of the leaf when iodine is applied M2 - ...after 1 day S - We will control the temperature of the room

Question 153

2.23 practical: carbon dioxide & photosynthesis

Answer 153

de-starch the plant by placing it in a dark cupboard for 24 hours following destarching, enclose 1 leaf with a conical flask containing potassium hydroxide potassium hydroxide will absorb carbon dioxide from the surrounding air enclose another leaf with a conical flask containing no potassium hydroxide (control experiment) place the plant in bright light for several hours test both leaves for starch using iodine solution drop the leaf in boiling water transfer the leaf into hot ethanol in a boiling tube for 5-10 minutes rinse the leaf in cold water spread the leaf out on a white tile and cover it with iodine solution the leaf from the conical flask containing potassium hydroxide will remain orange-brown - couldn't photosynthesise due to lack of carbon dioxide the leaf from the conical flask not containing potassium hydroxide should turn blue-black as it had all necessary requirements for photosynthesis

Question 154

2.23 practical: CORMS evaluation carbondioxide & photosynthesis

Answer 154

C - We are changing whether there is carbon dioxide or no carbon dioxide O - The leaves will be taken from the same plant or same species, age and size of plant R - We will repeat the investigation several times to ensure our results are reliable M1 - We will observe the colour change of the leaf when iodine is applied M2 - ...after 1 day S - We will control the temperature of the room and the light intensity

Question 155

2.23 practical: investigating chlorophyll & photosynthesis

Answer 155

drop the leaf in boiling water This kills the tissue and breaks down the cell walls transfer the leaf into hot ethanol in a boiling tube for 5-10 minutes this removes the chlorophyll so colour changes from iodine can be seen more clearly rinse the leaf in cold water this is done to soften the leaf tissue after being in ethanol spread the leaf out on a white tile and cover it with iodine solution the white areas of the leaf contain no chlorophyll and when the leaf is tested only the areas that contain chlorophyll stain blue-black the areas that had no chlorophyll remain orange-brown as no photosynthesis is occurring here and so no starch is stored

Question 156

2.23 practical: CORMS evaluation for chlorophyll and photosynthesis

Answer 156

C - We are changing whether there is chlorophyll or no chlorophyll O - The leaves will be taken from the same plant or same species, age and size of the plant R - We will repeat the investigation several times to ensure our results are reliable M1 - We will observe the colour change of the leaf when iodine is applied M2 - ...after 1 day S - We will control the temperature of the room and the light intensity

Question 157

2.24 what are the key food groups are for a balanced diet

Answer 157

carbohydrates proteins lipids dietary fibre vitamins minerals (mineral ions) water

Question 158

2.25 carbohydrates what food source what function

Answer 158

bread, potatoes, rice, cereals & fruit fuel for respiration source of energy

Question 159

2.25 proteins what food source what function

Answer 159

meat, eggs, fish, quinoa & quorn growth and repair of cells and tissues fuel for respiration

Question 160

2.25 lipids (fats) what food source what function

Answer 160

butter, oil, nuts, cream & avocados store of energy thermal (and electrical) insulation fuel for respiration

Question 161

2.25 dietary fibre what food source what function

Answer 161

vegetables, whole grains provides bulk for the intestine to push food through it

Question 162

2.25 vitamins what food source what function

Answer 162

fruits and vegetables needed in small quantities to maintain health

Question 163

2.25 minerals what food source what function

Answer 163

fruits and vegetables, meats, dairy products needed in small quantities to maintain health

Question 164

2.25 water what food source what function

Answer 164

water, juice, milk, fruits & vegetables needed for chemical reactions to take place in cells

Question 165

2.25 calcium what food source what function

Answer 165

milk, cheese, eggs for strong teeth and bones (involved in the clotting of blood) deficiency leads to osteoporosis later in life

Question 166

2.25 vitamin D what food source what function

Answer 166

oily fish, dairy products (also made naturally by body in sunlight) helps body to absorb calcium & required for strong bones and teeth

Question 167

2.25 vitamin C what food source what function

Answer 167

citrus fruits, strawberries, green vegetables forms an essential part of collagen protein - makes up skin, hair, gums & bones deficiency causes scurvy

Question 168

2.25 vitamin A what food source what function

Answer 168

meat, liver, dairy, leafygreen vegetables (spinach), eggs needed to make the pigment in the retina for vision

Question 169

2.25 iron what food source what function

Answer 169

red meat, liver, leafygreen vegetables (spinach) needed to make haemoglobin ^ pigment in redbloodcells that transports oxygen

Question 170

2.26 energy requirements for age

Answer 170

the amount needed in young people increases towards adulthood - energy is needed for growth children need a higher proportion of protein than adults for growth energy for adults decrease as they age

Question 171

2.26 energy requirements for activity levels

Answer 171

the more active, the more energy required for movement as muscles are contracting more and respiring faster

Question 172

2.26 energy requirements for pregnancy

Answer 172

requirements increase as energy is needed to support the growth of the developing foetus extra calcium & iron are needed to help build the bones, teeth and blood of the foetus

Question 173

2.27 function of the mouth

Answer 173

where mechanical digestion takes place teeth chew food - smaller pieces amylase enzymes in saliva digest starch into maltose shaped into bolus so it can be swallowed

Question 174

2.27 function of the oesophagus

Answer 174

connects mouth to the stomach contractions take place to push bolus down

Question 175

2.27 function of the stomach

Answer 175

food's mechanically digested by churning protease enzymes chemically digest proteins hydrochloric acid kills bacteria & optimum pH for protease enzymes to work

Question 176

2.27 function of the small intestine (duodenum)

Answer 176

food coming out stomach finishes being ^ - digested by enzymes produced here & also secreted from the pancreas ! slightly alkaline pH 8-9

Question 177

2.27 function of the small intestine (ileum)

Answer 177

where absorption of digested food - molecules takes place long & lined with villi - increasing surface - area where absorption can take place ! slightly alkaline pH 8-9

Question 178

2.27 function of the large intestine (colon & rectum)

Answer 178

water is absorbed from remaining material in the COLON to produce faeces faeces is stored in the rectum and removed through the anus

Question 179

2.27 function of the pancreas

Answer 179

produces amylase, protease & lipase secretes enzymes is an alkaline fluid into the duodenum(LARGEint) to raise pH of fluid coming out of the stomach

Question 180

2.27 what are the 6 structures in the alimentary canal

Answer 180

mouth, oesophagus, stomach, small intestine, large intestine & pancreas

Question 181

2.27 the stages of food breakdown

Answer 181

ingestion - taking in substances, mechanical digestion - breaking food into smaller pieces chemical digestion - large, insoluble molecules broken down into small, soluble molecules absorption - movement of small food molecules and ions through the wall of the intestine into the blood assimilation - movement of digested food molecules into body where they are used, becoming part of the cells egestion - passing out undigested or unabsorbed food (as faeces) through the anus

Question 182

2.28 how is food moved through the gut by peristalsis

Answer 182

muscles in the walls of the oesophagus create waves of contractions - forcing the bolus along once the bolus has reached the stomach, it turns into chyme - continues on to the small intestine peristalsis is controlled by circular & longitudinal muscles mucus is produced to continually lubricate the food mass and reduce friction dietary fibre provides the roughage required for the muscles to push against during peristalsis

Question 183

2.28 what mechanism pushes food through the gut

Answer 183

peristalsis

Question 184

2.29 protein ——>

Answer 184

protein —(pepsin)—> [peptides] —(trypsin)—> amino acids

Question 185

2.29 (carbohydrates?) starch ——>

Answer 185

(carbohydrates?) starch —(amylase)—> [maltose] —(maltase)—> glucose

Question 186

2.29 lipids ——>

Answer 186

lipids —(lipase)—> glycerol & fatty acids

Question 187

2.29 what enzyme breaks down protein into peptides what enzyme breaks down peptides amino acids

Answer 187

protease: pepsin pepsin is made in the stomach protease: trypsin trypsin is made in the pancreas & small intestine

Question 188

2.29 what enzyme breaks down carbohydrates into maltose what enzyme breaks down maltose into glucose

Answer 188

carbohydrase: amylase amylase is made in pancreas and salivary glands carbohydrase: maltase maltase is made in pancreas

Question 189

2.29 what enzyme breaks down lipids into fatty acids and glycerol

Answer 189

lipase: lipase enzymes lipase enzymes are produced in the pancreas

Question 190

2.30 where is bile produced

Answer 190

in the liver

Question 191

2.30 where is bile stored

Answer 191

in the gall bladder

Question 192

2.31 what does bile do to stomach acid

Answer 192

it neutralises the hydrochloric stomach acid

Question 193

2.31 what does bile do to lipids

Answer 193

it emulsifying lipids

Question 194

2.31 how does bile neutralise stomach acid

Answer 194

the alkaline properties in it allow it to neutralise the hydrochloric acid the neutralisation is essential as enzymes in small intestine have higher optimum pH

Question 195

2.31 how does bile emulsify lipids

Answer 195

it breaks apart large drops of fat into smaller ones (increasing their surface area)

Question 196

2.32 how is the small intestine adapted for absorption

Answer 196

it is very long and has a highly folded surface with millions of villi which increase the surface area allowing absorption to take place faster and more efficiently peristalsis helps by mixing food and enzymes and keeping things moving

Question 197

2.32 how is the structure of a villus adapted for absorption

Answer 197

a large surface area: microvilli on the surface short diffusion distance: one cell thick walls steep concentration gradient: - surrounded by a network of blood capillaries - transport glucose&amino acids away - a lacteal to transport fatty acids and glycerol away

Question 198

2.33B practical: energy content of a food sample practical:

Answer 198

measure 25cm3 of water pour into boiling tube record starting temp food is lit over bunsen burner hold food under boiling tube to heat it (if food stops burning relight it) relight until food no longer burns measure finishing temp of water calculate the temp change

Question 199

2.34 how does the process of respiration produce ATP

Answer 199

energy is released from glucose either in the presence of oxygen (aerobic) or no oxygen (anaerobic) resulting in the production of carbon dioxide and water as waste products energy is transferred in the form of ATP

Question 200

2.35 what does ATP provide for cells

Answer 200

ATP provides energy for cells (muscle contractions & keeping warm - painting a constant temperature)

Question 201

2.36 differences between aerobic & anaerobic respiration with oxygen

Answer 201

aerobic needs oxygen anaerobic doesn't need oxygen

Question 202

2.36 differences between aerobic & anaerobic respiration with the breakdown of glucose

Answer 202

breakdown is complete in aerobic breakdown is incomplete in anaerobic

Question 203

2.36 differences between aerobic & anaerobic respiration with the products

Answer 203

aerobic = carbon dioxide & water anaerobic = anima cells: lactic acid yeast: carbon dioxide & ethanol

Question 204

2.36 differences between aerobic & anaerobic respiration with the energy released

Answer 204

aerobic releases a lot of energy anaerobic releases a little

Question 205

2.37 word equation for aerobic respiration

Answer 205

glucose + oxygen → carbon dioxide + water

Question 206

2.37 the balanced chemical symbol equation for aerobic respiration

Answer 206

C6H12O6 + 6O2 → 6CO2 + 6H20

Question 207

2.38 the word equation for anaerobic respiration in animals

Answer 207

glucose ---> lactic acid

Question 208

2.38 the word equation for anaerobic respiration in plants

Answer 208

glucose ---> ethanol + carbon dioxide

Question 209

2.39 practical: evolution of carbon dioxide from respiring seeds

Answer 209

measure out 10 cm3 of hydrogencarbonate indicator into 3 boiling tubes put in a layer of cotton wool place 10 germinating seeds in tube A place 10 boiled/dead seeds in tube B place 10 glass beads in tubeC seal each tube with a rubber bung after 3 hours, observe the colour of the indicator high CO2 = yellow atmospheric CO2 = orange low CO2 = purple

Question 210

2.39 practical: demonstrating the production of heat from respiring seeds

Answer 210

flask A with the dead seeds flask B with the germinating seeds make sure the cotton wool is plugging the top of each flask hold the thermometer in place with the cotton wool invert the flask record the initial temperature after 4 days, record the final temperature

Question 211

2.39 practical: analysis

Answer 211

the thermometer in the flask with the germinating seeds (Flask B) should show an increase in temperature - the seeds in flask B are respiring and producing heat energy in the process flask A should remain at room temperature the seeds in flask A are not respiring because they are dead, so the temperature remains the same this shows that respiration is an exothermic reaction

Question 212

2.39 practical: CORMS evaluation evolution of carbon dioxide

Answer 212

change - we will change the content of the boiling tube (germinating seeds, dead seeds or glass beads) organisms - the seeds used should all be of the same age, size and species repeat - we will repeat the investigation several times to ensure our results are reliable measurement 1 - we will observe the change in the hydrogen carbonate indicator measurement 2 - ...after 3 hours same - we will control the volume of hydrogen carbonate indicator, the number of seeds/beads, the temperature of the environment

Question 213

2.39 practical: CORMS evaluation evolution of heat

Answer 213

change - we will change the content of the flasks (germinating seeds or dead seeds) organisms - the seeds used should all be of the same age, size and species repeat - repeat the investigation several times to ensure our results are reliable measurement 1 - change in the temperature on the thermometer measurement 2 - ...after 4 days same - control the number of seeds, the starting temperature of the flasks, the material and size of the flasks

Question 214

2.40B what is diffusion

Answer 214

diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration

Question 215

2.40B what happens in diffusion

Answer 215

molecules move down a concentration gradient as a result of their random movement

Question 216

2.40B what does diffusion do in regards to gas exchange

Answer 216

diffusion drives the process of gas exchange

Question 217

2.40B what organisms can exchange gases by simple diffusion through the cell membrane

Answer 217

single-celled organisms such as amoeba

Question 218

2.40B what can single-celled organisms (amoeba) do through the cell membrane

Answer 218

they can exchange gases sufficiently by simple diffusion through the cell membrane

Question 219

2.40B what organisms have exchange surfaces and organ systems that maximise the exchange of materials

Answer 219

multicellular organisms

Question 220

2.40B what do multicellular organisms have that maximise the exchange of materials

Answer 220

exchange surfaces and organ systems

Question 221

2.40B name examples of gas exchange organs in organisms

Answer 221

gills in fish, lungs in humans & leaves / roots in plants

Question 222

2.40B how do gas exchange organs increase the efficiency of exchange

Answer 222

they have a large surface area to increase the rate of transport they have a short diffusion distance for substances to move across (animals have gas exchange surfaces that are well-ventilated to maintain steep concentration gradients)

Question 223

2.41B what do the processes of respiration and photosynthesis both rely on

Answer 223

the exchange of oxygen and carbon dioxide

Question 224

2.41B what do all living cells do in gas exchange during respiration

Answer 224

all living cells respire

Question 225

2.41B what does the process of gas exchange during respiration require

Answer 225

the uptake of oxygen and the release of carbon dioxide

Question 226

2.41B how does oxygen diffuse in gas exchange during respiration

Answer 226

oxygen diffuses down the concentration gradient from a high concentration (outside the leaf) to a low concentration (inside the leaf)

Question 227

2.41B what do the cells use in respiration so the concentration is low

Answer 227

the cells use oxygen in respiration so the concentration is always low inside the respiring cells

Question 228

2.41B how does carbon dioxide diffuse in gas exchange during respiration

Answer 228

the carbon dioxide diffuses down the concentration gradient from a high concentration (inside the leaf) to a low concentration (outside the leaf)

Question 229

2.41B when do plant cells photosynthesise during gas exchange during photosynthesis

Answer 229

when there is enough sunlight

Question 230

2.41B what does the process of gas exchange during photosynthesis require

Answer 230

it requires the uptake of carbon dioxide and the release of oxygen

Question 231

2.41B how does carbon dioxide diffuse in gas exchange during photosynthesis

Answer 231

carbon dioxide diffuses down the concentration gradient from an area of high concentration (outside the leaf) to an area of low concentration (inside the leaf)

Question 232

2.41B what do the cells use in photosynthesis so the concentration is low

Answer 232

the cells use carbon dioxide in photosynthesis so the concentration is always low inside the photosynthesizing cells

Question 233

2.41B how does oxygen diffuse in gas exchange during photosynthesis

Answer 233

oxygen diffuses down the concentration gradient from a high concentration (inside the leaf) to a low concentration (outside the leaf)

Question 234

2.41B in photosynthesis where do carbon dioxide and oxygen diffuse

Answer 234

carbon dioxide diffuses into the leaf oxygen diffuses out of the leaf

Question 235

2.41B in photosynthesis what diffuses into the leaf and out of the leaf

Answer 235

carbon dioxide diffuses into the leaf oxygen diffuses out of the leaf

Question 236

2.42B the structure of a leaf is adapted for what

Answer 236

both photosynthesis and gas exchange

Question 237

2.42B name some things found inside a leaf

Answer 237

cuticle upper epidermis (bricks) palisade mesophyll (longer rectangles) xylem & phloem spongy mesophyll (air bubbles) lower epidermis (smaller bricks w/ hole) guard cell (hole in lower epidermis) cuticle

Question 238

2.41B in respiration what diffuses out of the leaf and what diffuses in

Answer 238

carbon dioxide diffuses out of the leaf and oxygen diffuses into the leaf

Question 239

2.41B in respiration where do carbon dioxide and oxygen diffuse

Answer 239

carbon dioxide diffuses out of the leaf and oxygen diffuses into the leaf

Question 240

2.41B how does gas exchange occur in a single-celled organism

Answer 240

in a single celled organism (like an amoeba) gas exchange occurs through diffusion

Question 241

2.42B what is the leaf specifically adapted to do

Answer 241

to maximise gas exchange

Question 242

2.42B what are the 3 key gases to consider in gas exchange in a leaf

Answer 242

carbon dioxide - released in respiration but used in photosynthesis oxygen - released in photosynthesis but used in respiration water vapour - released in respiration and transpiration

Question 243

2.42B where will gases always diffuse in a leaf

Answer 243

they will always diffuse down a concentration gradient (where there is a high concentration to where there is a low concentration)

Question 244

2.42B what is the pathway of carbon dioxide from the atmosphere to chloroplasts by diffusion

Answer 244

atmosphere -> through the open stoma -> air spaces around spongy mesophyll -> diffuses through cell wall & membrane of mesophyll cells -> dissolves in cytoplasm -> diffuses into chloroplast

Question 245

2.42B what are some adaptations of the whole leaf for gas exchange

Answer 245

thin which gives a short diffusion distance flat which provides a large surface area to volume ratio they have many stomata which allow movement of gases in and out of the air spaces by diffusion

Question 246

2.42B what are some adaptations of the internal leaf structures / tissues for gas exchange

Answer 246

air spaces to allow gas movement around the loosely packed mesophyll cells many stomata in the lower epidermis open in sunlight to allow gas movement in and out of the leaf thin cell walls allow gases to move into the cells easily moist air which gases can dissolve into for easier movement into and out of cells close contact between the cells and the air spaces allows efficient gas exchange for photosynthesis and respiration

Question 247

2.43B where are the stomata

Answer 247

they are found between two guard cells predominantly on the lower epidermis of the leaf

Question 248

2.43B what are the guard cells responsible for

Answer 248

for the opening and closing of the stomatal pore which controls gas exchange and water loss

Question 249

2.43B what does the stomatal pore do

Answer 249

it controls the gas exchange and water loss

Question 250

2.43B how does water move in regards to the stomata

Answer 250

the stomata opens when water moves by osmosis into the guard cells

Question 251

2.43B when water moves into the guard cells this makes them

Answer 251

turgid

Question 252

2.43B when guard cells are turgid this allows

Answer 252

gases to diffuse in and out of the leaf through the stomatal pore

Question 253

2.43B when do stomata tend to open

Answer 253

stomata tend to open when there is plenty of water and sunlight

Question 254

2.43B when do the stomata close

Answer 254

they close when the guard cells lose water by osmosis

Question 255

2.43B where does the water move to when the stomata close

Answer 255

it moves to the neighbouring epidermal cells and they become flaccid

Question 256

2.43B what do the epidermal cells become when water enters them

Answer 256

flaccid

Question 257

2.43B what does flaccid prevent

Answer 257

it prevents any diffusion in or out of leaf

Question 258

2.43B when do stomata tend to close

Answer 258

they tend to close due to low water availability or low sunlight

Question 259

2.43B what do the guard cells do

Answer 259

the guard cells control the opening and closing of the stomata

Question 260

2.44B when do plants photosynthesise

Answer 260

they photosynthesise when they have access to light however cells respire all the time

Question 261

2.44B what does this mean for gas exchange during a 24 hour period

Answer 261

gas exchange in plants varies throughout a 24 hour period

Question 262

2.44B what happens during the daytime with plants

Answer 262

during the daytime they both respire and photosynthesise

Question 263

2.44B in the day which rate is higher photosynthesis or respiration

Answer 263

photosynthesis tend to be higher - unless there is a low light intensity

Question 264

2.44B in the daytime what does this mean for carbon dioxide and oxygen in the plant

Answer 264

there is a net diffusion of carbon dioxide into the plant and a net diffusion of oxygen out of the plant during the day

Question 265

2.44B during the night time what do plants do

Answer 265

they only respire

Question 266

2.44B in the nighttime what does this mean for carbon dioxide and oxygen in the plant

Answer 266

this means that there is a net movement of oxygen into the plant and a net diffusion of carbon dioxide out of the plant during the nighttime

Question 267

2.44B what happens at low light intensities

Answer 267

the rate of photosynthesis is equal to the rate of respiration

Question 268

2.44B at low light intensities what does this mean for carbon dioxide and oxygen

Answer 268

this means that there is no net movement of oxygen or carbon dioxide in either direction

Question 269

2.44B what do plants do in the day and night

Answer 269

plants photosynthesise and respire during the day but only respire at night time

Question 270

2.45B practical: what apparatus do you need for the effect of light on gas exchange in plants

Answer 270

Boiling tubes Cotton wool Aluminium foil Gauze Rubber bungs Hydrogencarbonate indicator Leaves

Question 271

2.45B practical: method for the effect of light on gas exchange in plants

Answer 271

measure out 20cm3 of hydrogencarbonate indicator into 4 boiling tubes place cotton wool in the tubes label the boiling tubes A-D tube a - no leaf (control tube) tube b - place a leaf in tube and leave in the light tube c - place a leaf in the tube and wrap it in aluminium foil to block out the light tube d - place a leaf in then tube and wrap it in gauze place a bung on the top of each tube leave all 4 tubes in the light for 30 mins

Question 272

2.45B practical: what can hydrogencarbonate indicator be used for

Answer 272

it can be used to study gas exchange in different light conditions

Question 273

2.45B practical: results for the effect of light on gas exchange in plants

Answer 273

after 30 mins tube a - control tube should remain an orange / red colour as it is at atmospheric levels no net movement tube b - the leaf is photosynthesising and respiring because the rate of photosynthesis is greater than the rate of respiration the indicator will turn purple as there is less carbon dioxide than atmospheric levels tube c - no sunlight reached the leaf no light - leaf not photosynthesise but will respire producing carbon dioxide indicator turns yellow as carbon dioxide levels increase above atmospheric levels tube d - gauze allowed partial light rate of photosynthesis equals the rate of respiration so there was no net change in carbon dioxide levels indicator remains orange / red

Question 274

2.45B practical: what does hydrogencarbonate indicator change

Answer 274

it will change from orange / red to yellow with increasing carbon dioxide or purple with decreasing carbon dioxide

Question 275

2.45B practical: CORMS practical

Answer 275

- change - we will change the availability of light for each boiling tube (not wrapped, wrapped in foil, wrapped in gauze) - organisms - The leaves should be from the same species/age of the plant, they should be approximately the same size - repeat - We will repeat the investigation several times to ensure our results are reliable - measurement 1 - we will observe the change in the hydrogen carbonate indicator - measurement 2 - after 30 minutes - same - control the volume of hydrogen carbonate indicator, the number of leaves, the temperature of the environment

Question 277

2.46 what is the thorax

Answer 277

the human chest cavity

Question 278

2.46 what does the thorax consist of

Answer 278

the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes

Question 279

2.46 in the thorax describe the structure of the ribs

Answer 279

bone structure that protects internal organs such as the lungs

Question 280

2.46 in the thorax describe the structure of the intercostal muscles

Answer 280

muscles between the ribs which control their movement causing inhalation & exhalation

Question 281

2.46 in the thorax describe the structure of the diaphragm

Answer 281

sheet of connective tissue and muscle at the bottom of the thorax that helps change the volume of the thorax to allow inhalation & exhalation

Question 282

2.46 in the thorax describe the structure of the trachea

Answer 282

windpipe that connects the mouth and nose to the lungs

Question 283

2.46 in the thorax describe the structure of the larynx

Answer 283

also known as the voice box, when air passes across here we are able to make sounds

Question 284

2.46 in the thorax describe the structure of the bronchi (plural)

Answer 284

large tubes branching off the trachea with one bronchus (singular) for each lung

Question 285

2.46 in the thorax describe the structure of the bronchioles

Answer 285

bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli

Question 286

2.46 in the thorax describe the structure of the alveoli

Answer 286

tiny air sacs where gas exchange take place

Question 287

2.46 in the thorax describe the structure of the pleural cavity

Answer 287

the fluid filled space between the pleural membranes which reduces friction and allows the lungs to move freely

Question 288

2.46 the lungs are the ... surface in humans

Answer 288

gas exchange

Question 289

2.46 what features do all gas exchange surfaces have in common

Answer 289

large surface area for faster diffusion of gases across the surface thin walls to ensure diffusion distances remain short good ventilation with air so diffusion gradients can be maintained good blood supply to maintain a high concentration gradient so diffusion occurs faster

Question 290

2.47 muscles are only able to pull on bones not push them meaning

Answer 290

there must be two sets of intercostal muscles to work antagonistically to facilitate breathing

Question 291

2.47 what do the external intercostal muscles do

Answer 291

pull the ribcage up

Question 292

2.47 what do the internal intercostal muscles do

Answer 292

pull the ribcage down

Question 293

2.47 which intercostal muscles pull the ribcage up

Answer 293

the external intercostal muscles

Question 294

2.47 which intercostal muscles pull the ribcage down

Answer 294

the internal intercostal muscles

Question 295

2.47 what is the diaphragm

Answer 295

a thin sheet of muscle that separates the chest cavity from the abdomen

Question 296

2.47 during inhalation describe the diaphragm & intercostal muscles

Answer 296

external intercostal muscles contract ribcage moves up and out diaphragm contracts & flattens volume of thorax increases pressure inside thorax decreases - relative to the outside body - air is drawn in

Question 297

2.47 during exhalation describe the diaphragm & intercostal muscles

Answer 297

external intercostal muscles relax ribcage moves down and in diaphragm relaxes & becomes dome-shaped volume of thorax decreases pressure inside thorax increases - relative to the outside body - air is forced out

Question 298

2.48 how are alveoli highly adapted for gas exchange

Answer 298

large surface area to volume ratio: there are many rounded alveolar sacs minimise / short diffusion distance: alveoli have thin, single layers of cells steep concentration gradient: ventilation maintains high levels of oxygen & low levels of carbon dioxide good bloody supply & maintains concentration gradients: ensures a constant supply of blood high in carbon dioxide & low in oxygen a layer of moisture on the surface of the alveoli helps diffusion as gases dissolve

Question 299

2.49 smoking cigarettes has been linked to

Answer 299

disease in the lungs and is a risk factor in coronary heart disease

Question 300

2.49 what does nicotine in cigarettes do

Answer 300

narrows blood vessels and increases heart rate, leading to increased blood pressure causes high blood pressure that leads to blood clots forming in the arteries potentially resulting in heart attack or stroke

Question 301

2.49 what does carbon monoxide in cigarettes do

Answer 301

binds irreversibly to haemoglobin reducing the capacity of blood to carry oxygen breathing frequency & depth need to increase putting more strain on the breathing system circulatory system needs to pump blood faster - raising blood pressure & increasing risk of coronary heart disease & stroke

Question 302

2.49 what does tar in cigarettes do

Answer 302

it's a carcinogen linked to increased chances of cancerous cells developing in the lungs contributes to COPD which occurs when chronic bronchitis and emphysema occur together

Question 303

2.49 what happens in chronic bronchitis

Answer 303

tar stimulates goblet cells & mucus glands to enlarge and produce more mucus mucus builds up blocking the smallest bronchioles leading to infections build up of mucus can result in damage to the cilia preventing them from beating & removing the mucus a smokers cough is the attempt to move the mucus

Question 304

2.49 what happens in emphysema

Answer 304

phagocytes that enter the lungs release elastase an enzyme that breaks down the elastic fibres in the alveoli alveoli become less elastic & cannot stretch so many burst the breakdown of alveoli reduces the surface area for gas exchange patients become breathless & wheezy

Question 305

2.49 smoking can cause ... and several types of cancer including ...

Answer 305

coronary heart disease and lung cancer

Question 306

2.49 what does nicotine do

Answer 306

it narrows blood vessels - increased blood pressure increased heart rate

Question 307

2.49 what does carbon monoxide do

Answer 307

binds irreversibly to haemoglobin breathing frequency has to increase increases risk of coronary heart disease & strokes

Question 308

2.49 emphysema does what

Answer 308

makes the alveoli less elastic & cannot stretch the breakdown of alveoli reduces the surface area for gas exchange

Question 309

2.49 smoking increases the risk of cancer which is

Answer 309

the rapid uncontrolled cell growth

Question 310

2.49 tobacco smoke contains ______ ________ which permanently binds to the haemoglobin forming __________________ reducing the amount of oxygen being transported by the blood

Answer 310

carbon monoxide carboxyhaemoglobin

Question 311

2.49 in healthy lungs the linings of the trachea and bronchi are

Answer 311

specialised to prevent dirt and bacteria entering the lungs

Question 312

2.49 the cilia of the lining cells move transporting the mucus

Answer 312

up the airways where it is then swallowed

Question 313

2.49 chemicals in tobacco smoke destroy _____ reducing their number, at the same time mucus production will increase. the mucus cannot be moved out of the airways quickly so it ______ __ causing _______ _____ and increases the risk of infection

Answer 313

cilia builds up smokers cough

Question 314

2.49 __________ is a disease resulting from the build up of in refuted mucus in the bronchi and bronchioles

Answer 314

bronchitis

Question 315

2.49 smoke can also reach the alveoli damaging them: the alveoli walls break down in places and fuse together forming larger irregular air spaces this ___ the surface area for gas exchange so ____ oxygen diffuses into the blood, this disease is called _________ and kills around 20k people in Britain per year

Answer 315

decreases less emphysema

Question 316

2.49 chemicals in cigarettes include:

Answer 316

tar - a carcinogen (a substance that causes cancer) nicotine - an addictive substance which also narrows blood vessels carbon monoxide - reduces the oxygen-carrying capacity of the blood

Question 317

2.50 practical: the effect of excerise on breathing method

Answer 317

work out student A's breathing rate at rest count their number breaths for 15 seconds and multiply by 4 repeat to calculate an average student A should then exercise for a set time (at least 4 minutes) count the breaths taken in 15 seconds and multiply by 4 to obtain the breathing rate per minute compare the result to the breathing rate at rest in order to work out the change in breathing rate as a result of exercise repeat this last step every minute after exercise for 5 minutes repeat the process for student B finally, repeat the whole investigation for each student after a period of rest

Question 318

2.50 practical: the effect of exercise on breathing results

Answer 318

frequency of breathing increases when exercising this is because muscles are working harder and aerobically respiring more and they need more oxygen to be delivered to them (and carbon dioxide removed) to keep up with the energy demand if they cannot meet the energy demand they will also respire anaerobically, producing lactic acid

Question 319

2.50 practical: the effect of exercise on breathing analysis

Answer 319

after exercise has finished, the breathing rate remained elevated for a period of time this is because the lactic acid that has built up in muscles needs to be removed as it lowers the pH of cells and can denature enzymes catalysing cell reactions it can only be removed by combining it with oxygen - this is known as ‘repaying the oxygen debt’ this can be tested by seeing how long it takes after exercise for the breathing rate to return to normal the longer it takes, the more lactic acid produced during exercise and the greater the oxygen debt that needs to be repaid

Question 320

2.50 practical: what might an unfit individual have

Answer 320

higher breathing rate while resting more rapid increase in breathing rate during exercise longer recovery period for their breathing rate to return back to a normal resting rate

Question 321

2.50 practical: how do you control all variables

Answer 321

ensure students are similar size, general fitness, age, gender and provide each with the same meal before exercise

Question 322

2.50 practical: CORMS evaluation

Answer 322

change - We will change whether the student has exercised or not organisms - The students should be of the same age, gender, size and general fitness repeat - We will repeat the investigation several times to ensure our results are reliable measurement 1 - We will measure the change in breathing rate measurement 2 - ...immediately after exercise and each minute for the subsequent 5 minutes same - We will control the type of exercise carried out, the temperature of the environment, the food intake of the students prior to the investigation

Question 323

2.50 practical: exercise causes the frequency

Answer 323

exercise causes the frequency of breathing to increase in order to provide more oxygen for respiration and to pay off any subsequent oxygen debt

Question 324

2.50 practical: apparatus needed for the effect of exercise

Answer 324

a stop watch 2 students

Question 325

2.56B the loss of water vapour from the leaves is called

Answer 325

transpiration

Question 326

2.56B examiners definition of transpiration

Answer 326

the evaporation of water from the surface of a plant

Question 327

2.57B how does temperature affect the rate of transpiration

Answer 327

water will evaporate quickly as the water molecules have more kinetic energy

Question 328

2.57B how does humidity affect the rate of transpiration

Answer 328

humid air - water vapour = smaller conc gradient so transpiration slows down

Question 329

2.57B how does wind speed affect the rate of transpiration

Answer 329

moving air - water vapour blown away from leaf - speeds up transpiration

Question 330

2.57B transpiration .. as wind speed ..

Answer 330

transpiration increases as wind speed increases

Question 331

2.57B transpiration .. as humidity ..

Answer 331

transpiration increases as humidity decreases

Question 332

2.57B transpiration .. as temperature ..

Answer 332

transpiration increase as temp increases

Question 333

2.57B light intensity does NOT affect

Answer 333

evaporation

Question 334

2.57B how does light intensity affect the rate of transpiration

Answer 334

in daylight stomata leaves are open to supply CO2 for photosynthesis allows more water to diffuse out leaves into atmosphere

Question 335

2.58B practical: how to set up a potometer

Answer 335

set up underwater cut the stem shoot stem in bung grease joint w jelly (no air entry/water loss) bung in potometer tap closed full of water lift potometer out of water leave end of capillary tube out of water until air bubble forms & then put in beaker of water measure rate as distance bubble travelled in 5 mins

Question 336

2.58B practical: a potometer is to measure

Answer 336

measure the rate of water uptake from a leafy shoot

Question 337

2.58B practical: we can use potometer to collect readings in normal air or windy conditions by

Answer 337

using a hairdryer on cold

Question 338

2.58B practical: we can use potometer to collect readings in temperature

Answer 338

increases and decreases

Question 339

2.58B practical: we can use potometer to collect readings in increased humidity by

Answer 339

using a clear plastic bag

Question 340

2.58B practical: we can use potometer to collect readings by changing the l & d

Answer 340

lightness and darkness

Question 341

2.58B practical: changing the environmental factors stimulates

Answer 341

all the different conditions which affect the rate of transpiration

Question 342

2.67 what are the factors that may increase the risk of developing coronary heart disease?

Answer 342

1. obesity 2. high blood pressure 3. high cholestrol 4. smoking

Question 343

2.67 how can obesity increase risk of developing coronary heart disease?

Answer 343

carrying extra weight puts a strain on the heart. increased weight can lead to type 2 diabetes which further damages the blood vessels.

Question 344

2.67 how can high blood pressure increase risk of developing coronary heart disease?

Answer 344

high blood pressure increases the force of the blood against the artery walls and consequently leads to damage of the vessels.

Question 345

2.67 how can high cholestrol increase risk of developing coronary heart disease?

Answer 345

high cholestrol speeds up the build up of fatty plaques in the arteries which leads to blockages.

Question 346

2.67 how can smoking increase risk of developing coronary heart disease?

Answer 346

chemicals in smoke cause an increase in plaque build up and and increase in blood pressure. carbon monoxide also reduces the oxygen carrying capacity of the red blood cells.

Question 347

2.68 how many types of blood vessel are there? and name them

Answer 347

arteries, veins, capillaries. each vessel is specifically adapted to carry out its particular function efficiently.

Question 348

2.68 what are the smaller vessels that branch off from the arteries called?

Answer 348

arterioles (small arteries)

Question 349

2.68 what are the smaller vessels that branch into veins called ?

Answer 349

venules (small veins)

Question 350

2.68 what are the key features of arteries?

Answer 350

carry blood at high pressure away from the heart carry oxygenated blood (except pulmonary artery) have thick muscular walls containing elastic fibres have a narrow lumen blood flows through at a fast speed.

Question 351

2.68 how is the structure of an artery adapted to its function?

Answer 351

thick muscular walls containing elastic fibres withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through a narrow lumen also helps to maintain high pressure.

Question 352

2.68 what are the key features of veins?

Answer 352

carry blood at low pressure towards the heart carry deoxygenated blood (other than the pulmonary vein) have thin walls have a large lumen contain valves blood flows through a slow speed

Question 353

2.68 how is the structure of a vein adapted to its function?

Answer 353

a large lumen reduces resistance to blood flow under low pressure. valves prevent the backflow of blood as it is under low pressure

Question 354

2.68 what are the key features of capillaries?

Answer 354

carry blood at low pressure within tissues carry both oxygenated and deoxygenated blood have walls that are one cell thick have 'leaky' walls speed of blood flow is slow

Question 355

2.68 how is the structure of a capillary adapted to its function?

Answer 355

capillaries have walls that are one cell thick (short diffusion distance) so substances can easily diffuse in and out of them. The 'leaky' walls allow blood plasma to leak out and form tissue fluid surrounding cells.

Question 356

2.51 organisms must exchange what substances to function properly

Answer 356

food molecules and waste

Question 357

2.51 the exchange of food molecules and waste in organisms happens via

Answer 357

diffusion, osmosis and active transport across the cell membrane

Question 358

2.51 give an example of a unicellular organism

Answer 358

amoebas

Question 359

2.51 unicellular organisms like amoebas have what

Answer 359

large surface areas relative to their volume meaning the distance from the surface to the centre is small

Question 360

2.51 unicellular organisms like amoebas do not need

Answer 360

specialised exchange surfaces / transport systems

Question 361

2.51 what are the specialised exchange surfaces / transport systems that unicellular organisms do not need

Answer 361

transport systems such as diffusion, osmosis and active transport through the cell membrane

Question 362

2.51 in an amoeba what does the oxygen do

Answer 362

oxygen diffuses in for respiration

Question 363

2.51 in an amoeba what does the waste products - including CO2

Answer 363

waste products - including CO2 - diffuses out

Question 364

2.51 in an amoeba what does the water do

Answer 364

water moves in / out by osmosis

Question 365

2.51 what do unicellular organisms not require

Answer 365

unicellular organisms such as amoeba do not require transport systems due to their large surface area to volume ratio

Question 366

2.52 an example of a multicellular organism

Answer 366

humans - they are composed of many cells

Question 367

2.52 why are humans multicellular organisms

Answer 367

bodies are composed of many cells

Question 368

2.52 what do multicellular organisms have

Answer 368

they have multiple cell layers

Question 369

2.52 what do the multiple cell layers in organisms mean for the distance

Answer 369

the distance from the surface to the centre too long for diffusion alone

Question 370

2.52 larger multicellular organisms require what

Answer 370

transport systems

Question 371

2.52 why do larger organisms require transport systems

Answer 371

diffusion to all cells would be too slow to meet the organisms needs

Question 372

2.52 in animals what carries essential substances in the blood

Answer 372

circulatory system

Question 373

2.52 what is the transport system in animals

Answer 373

the circulatory system

Question 374

2.52 in plants what transports substances

Answer 374

vascular system

Question 375

2.52 what is the transport system in plants

Answer 375

vascular system

Question 376

2.52 what substances does the vascular system transport in plants

Answer 376

the xylem moves water and minerals from roots to shoots the phloem distributes sugars and amino acids throughout the plant

Question 377

2.52 what does the xylem do regarding transport systems in multicellular organisms

Answer 377

water and mineral ions from roots to shoots

Question 378

2.52 what does the phloem do regarding transport systems in multicellular organisms

Answer 378

sugars and amino acids from source to sink

Question 379

2.52 what does the circulatory system do regarding transport systems in multicellular organisms

Answer 379

blood carries oxygen, glucose, carbon dioxide, water & waste around the body

Question 380

2.52 what do multicellular systems have

Answer 380

transport systems

Question 381

2.53 what is the role of the phloem

Answer 381

it transports sucrose and amino acids from where they are produced / stored to where they are needed

Question 382

2.53 where are sucrose and amino acids produced

Answer 382

in the leaves while plants photosynthesise so they are transported from the leaves to the other parts of the plant

Question 383

2.53 what is the phloem formed by

Answer 383

it is formed from living cells forming a tube with small holes through which substances can move

Question 384

2.53 & 2.54 what do the xylem and phloem make up

Answer 384

the transport system of vascular plants

Question 385

2.53 & 2.54 what makes up the transport system of vascular plants

Answer 385

the xylem and phloem

Question 386

2.54 what is the role of the xylem

Answer 386

to transport water and mineral ions from the roots to other parts of the plant

Question 387

2.54 what is the xylem formed from

Answer 387

formed from a hollow tube of dead cells reinforced by lignin which provides a route for the column of water to move through the plant by transpiration

Question 388

2.54 what cell content does the xylem have

Answer 388

no cell contents just a continuous column of water

Question 389

2.54 what happens to the original cell wall in the xylem

Answer 389

original cell wall between cells has broken down

Question 390

2.54 what happens to the walls in the xylem

Answer 390

the walls are thickened with lignin

Question 391

2.54 what are the walls thickened with in the xylem

Answer 391

lignin

Question 392

2.54 what does the structure of the xylem allow

Answer 392

it allows it to function as a vessel for the transport of water through the plant

Question 393

2.55B what are root hairs

Answer 393

single-celled extensions of epidermis cells in the root

Question 394

2.55B where do root hairs grow

Answer 394

they grow between soil particles and absorb water and minerals from the soil

Question 395

2.55B how are root hair cells adapted for the efficient uptake of water - by osmosis - ad mineral ions - by active transport

Answer 395

they contain mitochondria which release energy for active transport root hairs increase the surface are of plant roots increasing the rate at which water and minerals can be taken up

Question 396

2.55B what are root hair cells adapted for

Answer 396

the efficient uptake of water by osmosis & mineral ions by active transport

Question 397

2.55B what does mitochondria do in root hair cells

Answer 397

they release energy for active transport

Question 398

2.55B what do root hairs do in regard to the surface area

Answer 398

they increase the surface area of plant roots, increasing the rate at which water and minerals can be taken up

Question 399

2.55B what do root hair cells take up

Answer 399

mineral ions and water from the soil

Question 400

2.55B which is taken up by active transport with root hair cells

Answer 400

mineral ions from the soil

Question 401

2.55B which is taken up by osmosis with root hair cells

Answer 401

water

Question 402

2.55B root hair cells take up mineral ions from the soil by

Answer 402

active transport

Question 403

2.55B water moves into the root hair cell by

Answer 403

osmosis

Question 404

2.55B the water concentration of the cell cytoplasm is

Answer 404

reduced due to the presence of mineral ions

Question 405

2.55B why is the water concentration of the cell cytoplasm is reduced

Answer 405

due to the presence of mineral ions

Question 406

2.55B what does the structure of a root specifically allow it to do

Answer 406

it allows it to maximise absorption of water by osmosis and mineral ions by active transport

Question 407

2.55B how does water move in the root hair cells

Answer 407

by osmosis into the root hair cells

Question 408

2.55B what does water move through in the root hair cells

Answer 408

the root cortex and into the xylem vessels

Question 409

2.55B when the water gets into the xylem what does it do

Answer 409

it is carried up the leaves where it enters mesophyll cells

Question 410

2.55B what is the pathway for the root of water through the root hair cell

Answer 410

root hair cell -> root cortex cells -> xylem -> leaf mesophyll cells

Question 411

2.59 what does the blood consist of

Answer 411

red blood cells, white blood cells, platelets & plasma

Question 412

2.59 how much of the blood is made up of plasma

Answer 412

over half

Question 413

2.59 statistics - percentage of what is in blood

Answer 413

55% plasma 45% red blood cells <1% white blood cells & platelets

Question 414

2.59 structure of red blood cells

Answer 414

biconcave discs containing no nucleus to maximise the available capacity to carry the protein haemoglobin

Question 415

2.59 structure of white blood cells

Answer 415

large cells containing a large nucleus - different types have slightly different structures and functions

Question 416

2.59 structure of platelets

Answer 416

fragments of cells

Question 417

2.59 structure of plasma

Answer 417

clear, straw -coloured aqueous solution

Question 418

2.60 what is plasma

Answer 418

a straw-coloured liquid which the other components of blood are suspended with

Question 419

2.60 what does plasma transport

Answer 419

carbon dioxide digested food and mineral ions urea hormones heat energy

Question 420

2.60 what is plasma important for

Answer 420

the transport of many substances

Question 421

2.60 plasma transports carbon dioxide explain more

Answer 421

carbon dioxide - waste product of respiration dissolved in plasma & transported from respiring cells to the lungs

Question 422

2.60 plasma transports digested food & mineral ions explain more

Answer 422

dissolved particles absorbed from the small intestine and delivered to requiring cells around the body

Question 423

2.60 plasma transports urea explain more

Answer 423

urea is a waste substance dissolved in the plasma and transported to the kidneys

Question 424

2.60 plasma transports hormones explain more

Answer 424

chemical messengers released into the blood from the endocrine organs (glands) and delivered to target tissues/organs of the body

Question 425

2.59 plasma transports heat energy explain more

Answer 425

heat energy (created in respiration) is transferred to cooler parts of the body or to the skin where heat can be lost

Question 426

2.60 plasma transports what substances & explain them

Answer 426

carbon dioxide - the waste product of respiration, dissolved in the plasma and transported from respiring cells to the lungs digested food and mineral ions - dissolved particles absorbed from the small intestine and delivered to requiring cells around the body urea - urea is a waste substance dissolved in the plasma and transported to the kidneys hormones - chemical messengers released into the blood from the endocrine organs (glands) and delivered to target tissues/organs of the body heat energy - heat energy (created in respiration) is transferred to cooler parts of the body or to the skin where heat can be lost

Question 427

2.61 what are red blood cells

Answer 427

they are specialised cells which carry oxygen to respiring cells

Question 428

2.61 how are red blood cells adapted to carry oxygen to respiring cells

Answer 428

- they are full of haemoglobin - they have no nucleus which allows more space for haemoglobin to be packed in - shaped as a biconcave disc which gives them a large surface area to volume ratio to maximise diffusion of oxygen in and out

Question 429

2.62 what are white blood cells a part of

Answer 429

the body's immune system

Question 430

2.62 what are white blood cells

Answer 430

they are specialised cells that defend against pathogenic microorganisms

Question 431

2.62 what are the two main types of white blood cell

Answer 431

phagocytes and lymphocytes

Question 432

2.62 what do phagocytes carry out

Answer 432

phagocytosis by ingesting pathogens

Question 433

2.62 how do phagocytes carry out phagocytosis

Answer 433

by ingesting pathogens

Question 434

2.62 phagocytes have what type of cell surface

Answer 434

a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells

Question 435

2.62 phagocytes have a sensitive cell surface membrane which

Answer 435

can detect chemicals produced by pathogenic cells

Question 436

2.62 when phagocytes encounter the pathogenic cell what do they do

Answer 436

they will engulf it and release digestive enzymes to digest it

Question 437

2.62 what type of response is phagocytosis

Answer 437

a non-specific immune response

Question 438

2.62 process of phagocytosis

Answer 438

bacterial pathogen is engulfed by the phagocyte (phagocytosis) digestive enzymes are released to destroy the bacteria

Question 439

2.62 what do lymphocytes do

Answer 439

they produce antibodies

Question 440

2.62 what are antibodies

Answer 440

they are proteins with a shape that is specific / complementary to the antigens on the surface of the pathogen

Question 441

2.62 what do lymphocytes provide

Answer 441

a specific immune response

Question 442

2.62 why do lymphocytes provide a specific immune response

Answer 442

as the antibodies produced will only fit one type of antigen on a pathogen

Question 443

2.62 what do lymphocytes do

Answer 443

they produce antibodies that are specific to the antigen on the pathogen

Question 444

2.62 what is the main component of the immune system

Answer 444

white blood cells

Question 445

2.62 what is the role of the immune system

Answer 445

when a pathogen enters the body, the immune system should prevent the infectious organism from reproducing and to destroy it

Question 446

2.62 when does an organism have immunity

Answer 446

when they have sufficient levels of antibodies to protect it from a particular disease

Question 447

2.62 what are the stages of infection

Answer 447

the pathogen enters the blood stream and multiplies it releases toxins & infects body cells causing symptoms in the patient phagocytes recognise the invading pathogen and engulf & digest it (non-specific response) the pathogen encounters a lymphocyte which recognises its antigens the lymphocyte produces specific antibodies to fight it the lymphocyte also clones itself to produce lots of lymphocytes - producing the specific antibody required antibodies destroy pathogens phagocytes engulf and digest destroyed pathogens

Question 448

2.62 stage 1 of the response to infection

Answer 448

the pathogen enters the blood stream and multiplies

Question 449

2.62 stage 2 of the response to infection

Answer 449

a release of toxins (in the case of bacteria) and infection of body cells causes symptoms in the patient

Question 450

2.62 stage 3 of the response to infection

Answer 450

phagocytes that encounter the pathogen recognise that it is an invading pathogen and engulf and digest (non-specific response)

Question 451

2.62 stage 4 of the response to infection

Answer 451

the pathogen encounters a lymphocyte which recognises its antigens

Question 452

2.62 stage 5 of the response to infection

Answer 452

the lymphocyte starts to produce specific antibodies to combat that particular pathogen

Question 453

2.62 stage 6 of the response to infection

Answer 453

the lymphocyte also clones itself to produce lots of lymphocytes (all producing the specific antibody required)

Question 454

2.62 stage 7 of the response to infection

Answer 454

antibodies destroy pathogens

Question 455

2.62 stage 8 of the response to infection

Answer 455

phagocytes engulf and digest the destroyed pathogens

Question 456

2.62 what is an antigen

Answer 456

is a molecule found on the surface of a cell

Question 457

2.62 what is an antibody

Answer 457

a protein made by lymphocytes that is complementary to an antigen and, when attached, clumps them together and signals the cells they are on for destruction

Question 458

2.63B what are vaccines used for

Answer 458

to induce immunity to infectious diseases

Question 459

2.63B what have vaccines done

Answer 459

they have reduced the cases of certain diseases or even eradicated them

Question 460

2.63B diseases vaccines have eradicated / reduced the case of

Answer 460

smallpox, measles, mumps and tetanus

Question 461

2.63B what does a vaccine contain

Answer 461

harmless versions of a pathogen

Question 462

2.63B what are the different methods scientists use to ensure the vaccines contain harmless pathogens

Answer 462

killing the pathogen (attenuated vaccine) which means making it unable to grow or divide using fragments of pathogens rather than whole cells

Question 463

2.63B how may a vaccine be administered

Answer 463

orally, nasally or via an injection

Question 464

2.63B how do vaccines work

Answer 464

when in the bloodstream the antigens in the vaccine trigger an immune response: lymphocytes recognise the antigens in the bloodstream the activated lymphocytes produce antibodies specific to the antigen encountered memory cells are produced from the lymphocytes memory cells and antibodies subsequently remain circulating in the blood stream

Question 465

2.63B what is the immune response vaccines trigger

Answer 465

lymphocytes recognise the antigens in the bloodstream the activated lymphocytes produce antibodies specific to the antigen encountered memory cells are produced from the lymphocytes memory cells and antibodies subsequently remain circulating in the blood stream

Question 466

2.63B how does long-term immunity work by vaccination

Answer 466

memory cells are produced when reacting & fighting the vaccine, so if the antigen is triggered again the antibodies are produced much faster

Question 467

2.63B future infection from the same pathogen to someone who was vaccinated means

Answer 467

the response will be much faster and much larger compared to the initial response

Question 468

2.63B why is an individual said to be immune after vaccinated

Answer 468

due to the rapid nature of the response, the pathogen is unable to cause disease

Question 469

2.64B what are platelets

Answer 469

they are fragments of cells

Question 470

2.64B what are platelets involved in

Answer 470

they are involved in blood clotting and forming scabs

Question 471

2.64B what happens after the skin is broken involving platelets

Answer 471

platelets arrive to stop the bleeding

Question 472

2.64B what is the series of reactions that occur within the blood plasma after the skin is broken

Answer 472

platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin this forms an insoluble mesh across the wound red blood cells become trapped, forming a clot the clot eventually dries and develops into a scab

Question 473

2.64B stage 1 of the series of reactions after the skin has been cut

Answer 473

platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin

Question 474

2.64B stage 2 of the series of reactions after the skin has been cut

Answer 474

there is an insoluble mesh formed across the wound

Question 475

2.64B stage 3 of the series of reactions after the skin has been cut

Answer 475

red blood cells become trapped, forming a clot

Question 476

2.64B stage 4 of the series of reactions after the skin has been cut

Answer 476

the clot eventually dries and develops into a scab

Question 477

2.64B how does the reactions that occur after a cut help the individual

Answer 477

it helps to prevent excessive blood loss and protect the wound from bacteria entering until new skin has formed

Question 478

2.65 what is the heart organ in terms of pumps

Answer 478

a double pump

Question 479

2.65 what is pumped into the left side of the heart from the lungs

Answer 479

oxygenated blood

Question 480

2.65 where does oxygenated blood from the lungs enter the heart

Answer 480

on the left side

Question 481

2.65 what is done with the oxygenated blood from the lungs when it is pumped into the left side of the heart

Answer 481

it is pumped to the rest of the body - the systemic circuit -

Question 482

2.65 which ventricle is thicker & why

Answer 482

the left has a thicker muscle wall as it has to pump blood at high pressure around the entire body

Question 483

2.65 which ventricle pumps blood around the whoe body

Answer 483

the left ventricle therefore it has a thicker muscle wall

Question 484

2.65 where does deoxygenated blood from the body enter the heart

Answer 484

on the right side

Question 485

2.65 what is pumped into the right side of the heart from the body

Answer 485

deoxygenated blood

Question 486

2.65 what is done with the deoxygenated blood from the body when it is pumped into the right side of the heart

Answer 486

it is pumped to the lungs - the pulmonary circuit -

Question 487

2.65 which side of the heart uses the pulmonary circuit

Answer 487

the right side with deoxygenated blood

Question 488

2.65 which side of the heart uses the systemic circuit

Answer 488

the left side with the oxygenated blood

Question 489

2.65 what pressure is the right ventricle pumping blood at

Answer 489

a lower pressure to the lungs

Question 490

2.65 what separates the two sides of the heart

Answer 490

the septum - muscle wall

Question 491

2.65 what does the septum - muscle wall - do in the heart

Answer 491

it separates the two sides of the heart

Question 492

2.65 where is blood pumped in veins

Answer 492

towards the heart

Question 493

2.65 where is blood pumped in arteries

Answer 493

away from the heart

Question 494

2.65 where is blood pumped towards the heart

Answer 494

in the veins

Question 495

2.65 what do the coronary arteries do

Answer 495

they supply the cardiac muscle tissue of the heart with oxygenated blood

Question 496

2.65 where is blood pumped away from the heart

Answer 496

in the arteries

Question 497

2.65 as the heart is a muscle what constant supply does it need

Answer 497

it needs a constant supply of oxygen (and glucose) for aerobic respiration to release energy to allow continued muscle contraction

Question 498

2.65 what do valves do

Answer 498

they prevent blood flowing backwards

Question 499

2.65 what prevents blood flowing backwards

Answer 499

valves

Question 500

2.65 why does the heart need a constant supply of oxygen (and glucose) for aerobic respiration to release energy to allow continued muscle contraction

Answer 500

because it is a muscle

Question 501

2.65 describe the flow of oxygenated blood in the heart

Answer 501

on the left side in through the pulmonary vein into the left atrium through the bicuspid valve into the left ventricle through the semi-lunar valves out of the aorta

Question 502

2.65 describe the flow of deoxygenated blood in the heart

Answer 502

on the right side in through the vena cava into the right atrium through the tricuspid valve into the right ventricle through the semi-lunar valves out of the pulmonary artery

Question 503

2.65 how to remember veins go into the heart

Answer 503

veIN into the heart

Question 504

2.65 how to remember arteries go away from the heart

Answer 504

Arteries are Away from the heart

Question 505

2.65 what is the pathway of blood through the heart BOTH DEOXYGENATED & OXYGENATED

Answer 505

DEOXYGENATED blood coming from the body flows through the vena cava and into the right atrium the atrium contracts and the blood is forced through the tricuspid valve into the right ventricle the ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery the blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place low pressure blood flow on this side of the heart prevents damage to the capillaries in the lungs OXYGENATED blood returns via the pulmonary vein to the left atrium the atrium contracts and forces the blood through the bicuspid valve into the left ventricle the ventricle contracts and the blood is forced through the semilunar valve and out through the aorta thicker muscle walls of the left ventricle produce a high enough pressure for the blood to travel around the whole body

Question 506

2.65 what is the pathway of blood through the heart - just DEOXYGENATED

Answer 506

DEOXYGENATED blood coming from the body flows through the vena cava and into the right atrium the atrium contracts and the blood is forced through the tricuspid valve into the right ventricle the ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery the blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place low pressure blood flow on this side of the heart prevents damage to the capillaries in the lungs

Question 507

2.65 what is the pathway of blood through the heart - just OXYGENATED

Answer 507

OXYGENATED blood returns via the pulmonary vein to the left atrium the atrium contracts and forces the blood through the bicuspid valve into the left ventricle the ventricle contracts and the blood is forced through the semilunar valve and out through the aorta thicker muscle walls of the left ventricle produce a high enough pressure for the blood to travel around the whole body

Question 508

2.66 how is the heart rate measured

Answer 508

by counting the number of times the heart beats in a minute - bpm

Question 509

2.66 the natural resting heart rate is controlled by what

Answer 509

a group of cells located in the right atrium called the pacemaker

Question 510

2.66 what is the role of the pacemaker

Answer 510

to coordinate the contraction of the heart muscle & regulate the heart rate

Question 511

2.66 how does the pacemaker function

Answer 511

pacemaker cells send out electrical impulses which initiate a contraction in the cardiac muscle

Question 512

2.66 why does the heart pumps blood to respiring cells

Answer 512

to supply oxygen and glucose and remove respiratory waste

Question 513

2.66 during exercise what do muscle cells do

Answer 513

they respire faster to increase energy supply

Question 514

2.66 when is respiration aerobic & anaerobic

Answer 514

aerobic during moderate exercise and anaerobic during intense exercise

Question 515

2.66 what types of respiration occur during moderate & intense exercise

Answer 515

aerobic during moderate exercise and anaerobic during intense exercise

Question 516

2.66 why do muscles respire faster during exercise

Answer 516

to increase energy supply

Question 517

2.66 what do muscles do during exercise

Answer 517

they respire faster

Question 518

2.66 how do muscle cells increase the energy supply during exercise

Answer 518

they respire faster

Question 519

2.66 what does increased respiration raise the need for

Answer 519

oxygen, glucose and waste removal

Question 520

2.66 how does the nervous system respond to an increased respiration rate

Answer 520

increasing heart rate to deliver oxygen and glucose more frequently & increasing the volume of blood pumped to supply larger amounts of oxygen and glucose

Question 521

2.66 what happens to the heart rate at the end of exercise

Answer 521

it main remain high as oxygen is required in the muscles to break down the lactic acid from anaerobic respiration

Question 522

2.66 why does heart rate remain high after exercise

Answer 522

it main remain high as oxygen is required in the muscles to break down the lactic acid from anaerobic respiration

Question 523

2.66 production of the hormone adrenaline also does what

Answer 523

it also increases heart rate as part of a 'fight or flight' response

Question 524

2.66 as part of the fight or flight response what hormone is released

Answer 524

adrenaline

Question 525

2.66 what hormone increases the heart rate

Answer 525

adrenaline

Question 526

2.67 what are the coronary arteries

Answer 526

the blood vessels which supply cardiac muscle with oxygen glucose

Question 527

2.67 what happens in coronary heart disease

Answer 527

layers of fatty material (plaque) build up inside the coronary arteries

Question 528

2.66 what are the fatty deposits in coronary heart disease made from

Answer 528

the fatty deposits are mainly formed from cholesterol

Question 529

2.66 where are the two main sources of cholesterol in the body

Answer 529

dietary cholesterol - from animal products eaten cholesterol synthesised by the liver

Question 530

2.66 what happens to the artery wall when plaque builds up

Answer 530

it becomes less elastic

Question 531

2.66 what is plaque made from

Answer 531

cholesterol and white blood cells

Question 532

2.66 what happens to the coronary artery when plaque builds up

Answer 532

coronary artery narrows restricting blood flow

Question 533

2.66 what can lead to coronary heart disease

Answer 533

a diet too high in saturated fat and cholesterol

Question 534

2.66 what does a buildup of plaque in the coronary arteries do

Answer 534

it narrows the lumen

Question 535

2.66 what happens if coronary artery becomes partially or completely blocked by these fatty deposits

Answer 535

the flow of blood through the arteries is reduced, resulting in a lack of oxygen for the heart muscle

Question 536

2.66 what does partial blockage do to the coronary arteries

Answer 536

it creates a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina

Question 537

2.66 what does complete blockage do to the coronary arteries

Answer 537

means cells in that area of the heart will not be able to respire aerobically, leading to a heart attack

Question 538

2.66 what is the effect of a narrowed lumen in a coronary artery

Answer 538

reduced blood flow to the heart

Question 539

2.66 what does carrying extra weight mean for CHD

Answer 539

carrying extra weight puts a strain on the heart increased weight can lead to type 2 diabetes which further damages your blood vessels

Question 540

2.66 what does a high blood pressure mean for CHD

Answer 540

this increases the force of the blood against the artery walls and consequently leads to damage of the vessels

Question 541

2.66 what does high cholesterol mean for CHD

Answer 541

speeds up the build up of fatty plaques in the arteries leading to blockages

Question 542

2.66 what does smoking mean for CHD

Answer 542

chemicals in smoke cause an increase in plaque build up and an increase in blood pressure carbon monoxide also reduces the oxygen carrying capacity of the red blood cells

Question 543

2.68 what are the three main types of blood vessel

Answer 543

arteries, veins or capillaries

Question 544

2.68 what are the smaller vessels that branch of arteries

Answer 544

arterioles (smaller arteries)

Question 545

2.68 what are arterioles

Answer 545

smaller arteries that branch off arteries

Question 546

2.68 what are the smaller vessels that branch of veins

Answer 546

venules (smaller veins)

Question 547

2.68 what are venules

Answer 547

smaller veins that branch off veins

Question 548

2.68 what do each blood vessel do

Answer 548

they have a particular function and are specifically adapted to carry out that function efficiently

Question 549

2.68 what are the key features of arteries?

Answer 549

carry blood at high pressure away from the heart carry oxygenated blood (except pulmonary artery) have thick muscular walls containing elastic fibres have a narrow lumen blood flows through at a fast speed.

Question 550

2.68 how is the structure of an artery adapted to its function?

Answer 550

thick muscular walls containing elastic fibres withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through a narrow lumen also helps to maintain high pressure

Question 551

2.68 what are the key features of veins?

Answer 551

carry blood at low pressure towards the heart carry deoxygenated blood (other than the pulmonary vein) have thin walls, have a large lumen, contain valves blood flows through a slow speed

Question 552

2.68 how is the structure of a vein adapted to its function?

Answer 552

a large lumen reduces resistance to blood flow under low pressure. valves prevent the backflow of blood as it is under low pressure

Question 553

2.68 what are the key features of capillaries?

Answer 553

carry blood at low pressure within tissues carry both oxygenated and deoxygenated blood have walls that are one cell thick have 'leaky' walls speed of blood flow is slow

Question 554

2.68 how is the structure of a capillary adapted to its function?

Answer 554

capillaries have walls that are one cell thick (short diffusion distance) so substances can easily diffuse in and out of them the 'leaky' walls allow blood plasma to leak out and form tissue fluid surrounding cells

Question 555

2.68 capillaries are the site of what

Answer 555

capillaries within body tissues where exchange of substances take place

Question 556

2.68 why are arterial walls thicker than vein walls

Answer 556

to withstand higher blood pressure

Question 557

2.69 the circulatory system consists of what

Answer 557

a closed network of blood vessels connected to the heart

Question 558

2.69 where oxygenated blood carried

Answer 558

oxygenated blood is carried away from the heart and towards organs in arteries

Question 559

2.69 the steps in network

Answer 559

oxygenated blood is carried away from the heart and towards organs in arteries these narrow to arterioles and then capillaries as they pass through the organ in the organs, respiring cells use up the oxygen from the blood the capillaries widen to venules and finally veins as they move away from the organs veins carry deoxygenated blood back towards the heart

Question 560

2.69 a different network of lymphatic vessels collect what

Answer 560

all the excess tissue fluid that leaks out of the capillaries and delivers it back to the circulatory system

Question 561

2.68 which network collects all the excess tissue fluid that leaks out of the capillaries and delivers it back to the circulatory system

Answer 561

lymphatic vessels

Question 562

2.69 what moves towards the heart

Answer 562

vena cava & pulmonary vein

Question 563

2.69 what moves away the heart

Answer 563

aorta & pulmonary artery

Question 564

2.69 what moves towards the lung

Answer 564

pulmonary artery

Question 565

2.69 what moves away the lung

Answer 565

pulmonary vein

Question 566

2.69 what moves towards the kidney

Answer 566

renal artery

Question 567

2.69 what moves away the kidney

Answer 567

renal vein

Question 568

2.71 what are the excretory products of the lungs

Answer 568

carbon dioxide (via blood plasma)

Question 569

2.71 what are the excretory products of the kidneys

Answer 569

urea

Question 570

2.71 what are the excretory products of the skin

Answer 570

urea

Question 571

2.71 water is lost from the body in the following ways:

Answer 571

via the lungs during exhalation (breathing out) lost from the skin as sweat (along side mineral ions and urea)

Question 572

2.72B what does the kidney do

Answer 572

it filters the blood and removes any excess materials and passes them to the bladder to be excreted

Question 573

2.72B the kidney contains millions of tiny structures called

Answer 573

nephrons

Question 574

2.72B nephrons are structures which

Answer 574

filter the blood

Question 575

2.72B what are the 3 main regions of the kidney

Answer 575

cortex, medulla and renal pelvis

Question 576

2.74B what are the 3 stages that occur in the nephron

Answer 576

ultrafiltration, selective reabsorption and water reabsorption

Question 577

2.74B the main sections in a nephron

Answer 577

bowman's capsule proximal convoluted tubule loop of henle distal convoluted tubule collecting duct

Question 578

2.74B surrounding the tubule is a network of

Answer 578

capillaries with a knotted section which sits inside the bowman's capsule

Question 579

2.74B where does the glomerulus sit

Answer 579

inside the bowmans capsule

Question 580

2.74B what shape is the bowmans capsule

Answer 580

cup shaped

Question 581

2.74B the glomerulus is a knot of

Answer 581

capillaries

Question 582

2.74B where is glucose reabsorbed

Answer 582

in the proximal first convoluted tubule

Question 583

2.74B the gates that facilitate the active transport of glucose are

Answer 583

only found in the proximal convoluted tubule

Question 584

2.74B the cells lining in the PCT have many mitochondria to

Answer 584

provide ATP (energy) for active transport

Question 585

2.74B the cells lining in the PCT have a folded membrane

Answer 585

to increase surface area

Question 586

2.74B where is water reabsorbed

Answer 586

loop of henle and collecting duct

Question 587

2.74B where are salts reabsorbed

Answer 587

loop of henle

Question 588

2.75B step1. the diameter of the efferent arteriole at the exit of the glomerulus is

Answer 588

smaller than the diameter of the afferent arteriole at the entrance causing a build up of pressure

Question 589

2.75B step1. the build up of pressure in the capillaries forms the

Answer 589

glomerulus

Question 590

2.75B step2. the pressure causes the smaller molecules being carried in the blood to be forced out of the capillaries and into

Answer 590

the bowman’s capsule where they form the glomerular filtrate

Question 591

2.75B step2. small molecules like urea, glucose, amino acids, water and salts are forced

Answer 591

out the glomerulus into the bowmans capsule

Question 592

2.75B step3. larger molecules like proteins or red blood cells are

Answer 592

too big to fit across the capillary wall so they stay in the blood

Question 593

2.75B where is water reabsorbed

Answer 593

loop of henle & collecting duct

Question 594

2.75B where are salts reabsorbed

Answer 594

loop of henle

Question 595

2.75B where is glucose reabsorbed

Answer 595

proximal first convoluted

Question 596

2.75B where is urea reabsorbed

Answer 596

it is NOT reabsorbed

Question 597

2.75B what small molecules are pushed through

Answer 597

urea, glucose, amino acids, water and salts

Question 598

2.75B what large molecules are too big to go through so stay in the blood

Answer 598

proteins and red blood cells

Question 599

2.75B what makes up the glomerular filtrate

Answer 599

urea, glucose, amino acids, water and salts

Question 600

2.77B after the glomerular filtrate enters the bowman’s capsule what's the first thing to be reabsorbed

Answer 600

glucose is the first substance to be reabsorbed at the proximal (first) convoluted tubule

Question 601

2.77B selective reabsorption takes place by

Answer 601

active transport

Question 602

2.77B the cells lining in the PCT have a folded membrane for

Answer 602

an increased surface area

Question 603

2.77B the cells lining in the PCT have many mitochondria to

Answer 603

provide ATP (energy) for active transport

Question 604

2.77B reabsorption of glucose cannot take place anywhere else in the nephron as

Answer 604

the gates that facilitate the active transport of glucose are only found in the proximal convoluted tubule

Question 605

2.79B urine contains

Answer 605

water, urea and ions

Question 606

2.79B if someone is diabetic their urine may contain

Answer 606

glucose

Question 607

2.79B urine produced by the kidneys contains a mixture of

Answer 607

urea excess mineral ions excess water

Question 608

2.79B small quantities of urine are usually darker yellow / orange in colour because

Answer 608

it contains little water and so the urea is more concentrated

Question 609

2.79B large quantities of urine are usually pale yellow in colour

Answer 609

because it contains a lot of water and so the urea is less concentrated

Question 610

2.77B where does selective reabsorption of glucose occur

Answer 610

in the proximal convoluted tubule

Question 611

2.79B what produces urine

Answer 611

the kidneys

Question 612

2.77B what's special about the reabsorption of glucose

Answer 612

its selectively reabsorped

Question 613

2.70 within plant cells there are a range of ... reactions taking place producing ... products

Answer 613

metabolic reactions producing waste products

Question 614

2.70 some waste products in plants are used up but others must exit the plant via

Answer 614

the leaf organ

Question 615

2.70 waste products / substances in excess inside the plant are

Answer 615

oxygen, carbon dioxide, water / water vapour, other unwanted chemical substances

Question 616

2.70 oxygen and carbon dioxide are both what in plants

Answer 616

reactants and waste products

Question 617

2.70 what are both reactants and waste products in plants

Answer 617

oxygen and carbon dioxide

Question 618

2.70 what affects the waste products within plants

Answer 618

the intensity of light

Question 619

2.70 during the day when there is sufficient light what happens inside the plant

Answer 619

the rate of photosynthesis is higher than the rate of respiration more oxygen is released than used in respiration less carbon dioxide is released than used in photosynthesis net effect - oxygen is in excess & a waste products

Question 620

2.70 during the night when there is insufficient light what happens inside the plant

Answer 620

there is no photosynthesis, only respiration oxygen is used in respiration and carbon dioxide is produced no photosynthesis means that no carbon dioxide is used net effect - carbon dioxide is in excess and a waste product

Question 621

2.70 what happens to the gas in excess

Answer 621

it diffuses out of the plant via the leaf organ the gases exit through the stomata

Question 622

2.70 where do the gases in excess diffuse out of the plant

Answer 622

through the stomata

Question 623

2.70 as the excretion of gases in plants occurs via diffusion it is technically

Answer 623

not an active process

Question 624

2.70 the majority of water vapour lost from a plant is not

Answer 624

not a waste product of metabolism

Question 625

2.70 what is the majority of water vapour lost from a plant

Answer 625

water that has been drawn up from the roots in the transpiration stream

Question 626

2.70 excretion in plants in the night:

Answer 626

carbon dioxide is excreted at night when the rate of respiration exceeds the rate of photosynthesis water vapour is excreted through transpiration

Question 627

2.70 excretion in plants in the day:

Answer 627

oxygen is excreted in the day when the rate of photosynthesis exceeds the rate of respiration water vapour is excreted through transpiration

Question 628

2.70 plant cells can do what to molecules

Answer 628

break them down

Question 629

2.70 plant cells can break down molecules into

Answer 629

chemical substances no longer required by the plant

Question 630

2.70 some of the substances in the plant cannot

Answer 630

be converted into another useful compound and so must be removed from the plant

Question 631

2.70 some of the substances in the plant must be removed from the plant because

Answer 631

they cannot be converted into another useful compound

Question 632

2.70 chemical waste materials in the plant are stored where

Answer 632

in the dying tissues of a plant

Question 633

2.70 when the dying tissues of a plant filled with chemical waste materials falls off

Answer 633

the substances are removed (in autumn leaves fall as different colors)

Question 634

2.73B two functions of the urinary system are

Answer 634

to filter waste products from the blood and expel it from the body as urine to control the water levels of the body (osmoregulation)

Question 635

2.73B the urinary system consists of

Answer 635

two kidneys joined to the bladder by two tubes called the ureters

Question 636

2.73B in another tube the urethra does what

Answer 636

the carries urine from the bladder to outside the body

Question 637

2.73B each kidney is connected to what

Answer 637

the renal artery which comes from the aorta and delivers oxygenated blood to the kidney the renal vein which delivers the deoxygenated blood from the kidney to the vena cava

Question 638

2.73B what are the structures in the urinary system

Answer 638

kidney ureter bladder urethra

Question 639

2.73B explain the kidney

Answer 639

two beam-shaped organs that filter the blood

Question 640

2.73B explain the ureter

Answer 640

tube connecting the kidney to the bladder

Question 641

2.73B explain the bladder

Answer 641

organ that stores urine as it is produced by the kidney

Question 642

2.79B what is urine

Answer 642

excess water, salts and urea

Question 643

2.73B explain the urethra

Answer 643

tube that connects the bladder to the exterior - where urine is released

Question 644

2.79B what does water contain

Answer 644

water, urea and salts

Question 645

2.76B what is reabsorbed when the filtrate drips through the loop of henle

Answer 645

necessary salts

Question 646

2.76B where are necessary salts reabsorbed

Answer 646

in the loop of henle

Question 647

2.76B how necessary salts reabsorbed

Answer 647

by diffusion and active transport

Question 648

2.76B as salts are reabsorbed in the loop of henle, what follows

Answer 648

water by osmosis

Question 649

2.76B how does water get reabsorbed into the blood

Answer 649

by osmosis

Question 650

2.76B water follows what as it is absorbed back in the blood

Answer 650

water follows salts being reabsorbed

Question 651

2.76B where is water reabsorbed

Answer 651

some in the loop of henle but most in the collecting duct

Question 652

2.76B water is reabsorbed in the collecting duct in different amounts why

Answer 652

depending on how much water the body needs at that time

Question 653

2.76B when ADH is released what happens in relation to water reabsorption

Answer 653

the permeability increases when permeability increases more water is absorbed

Question 654

2.76B where does water reabsorption occur

Answer 654

along the nephron tubules in the kidney

Question 655

2.76B why is water reabsorption important

Answer 655

its important for osmoregulation

Question 656

2.76B the control of water reabsorption by the tubules is an example of

Answer 656

negative feedback (when the feedback causes the corrective measures to be turned off so returns the system to its original / normal level)

Question 657

2.76B water is reabsorbed back into the blood stream by what process

Answer 657

renal tubular reabsorption

Question 658

2.76B where does renal tubular reabsorption take place

Answer 658

in the renal tubules which are small tube-like structures in the kidneys

Question 659

2.76B what are renal tubules

Answer 659

small tube-like structures in the kidneys

Question 660

2.76B what does diuresis mean

Answer 660

flow of urine from the body

Question 661

2.76B what does antidiuresis mean

Answer 661

producing less urine

Question 662

7.76B what happens when the loss of is detected

Answer 662

it is detected by receptor cells in the hypothalamus situated above the pituitary gland the cells are sensitive to the concentration of the blood so the pituitary gland releases more ADH the ADH travels in the blood to the kidneys at the kidney tubules the collecting ducts become more permeable to water so more water is reabsorbed

Question 663

2.76B any change in water level of the blood is detected by what

Answer 663

the hypothalamus

Question 664

2.76B what is negative feedback

Answer 664

change in conditions of the body is detected process is started to return body to normal when body is normal corrective process is switched off

Question 665

2.76B what does the hypothalamus do when it detects a change to the water level

Answer 665

it sends a signal to the pituitary gland in the brain

Question 666

2.76B what does the pituitary gland release

Answer 666

a hormone called ADH

Question 667

2.78B what does the pituitary gland release

Answer 667

a hormone called ADH

Question 668

2.76B how much ADH is released depends on

Answer 668

how much the kidneys need to reabsorb from the filtrate

Question 669

7.68B ADH affects what

Answer 669

the permeability of the tubules to water

Question 670

2.78B what is the role of ADH

Answer 670

it affects the permeability of the kidney tubules / the collecting duct of the kidney nephron more water reabsorbed - less water excreted

Question 671

2.76B if the water content is too high

Answer 671

the pituitary gland in the brain releases less ADH which leads to less water being reabsorbed in the collecting ducts of the kidney by osmosis (the collecting ducts become less permeable to water) as a result, the kidneys produce a large volume of dilute urine

Question 672

2.76B if the water content is too low

Answer 672

the pituitary gland releases more ADH which leads to more water being reabsorbed in the collecting ducts of the kidney by osmosis (the collecting ducts become more permeable to water) as a result, the kidneys produce a small volume of concentrated urine

Question 673

2.80 animals and plants respond to what

Answer 673

changes in their environment

Question 674

2.80 why do animals and plants need to be able to respond to changes

Answer 674

to coordinate the activities of their different organs

Question 675

2.80 what are examples of internal / external environment changes

Answer 675

changes in temperature or pH

Question 676

2.80 in order to function properly and efficiently organisms have

Answer 676

different control and communication systems that ensure their internal conditions are kept relatively constant

Question 677

2.81 physiological control systems maintain what

Answer 677

the internal environment with restricted limits through a process known as homeostasis

Question 678

2.81 what is homeostasis

Answer 678

the maintenance of a constant internal environment

Question 679

2.81 two examples of homeostasis

Answer 679

body water content and body temperature

Question 680

2.81 why is homeostasis critically important

Answer 680

it ensures the maintenance of optimal conditions for enzyme action and cell function

Question 681

2.81 examples of physiological factors that are controlled by homeostasis in mammals include

Answer 681

core body temperature metabolic waste (e.g. carbon dioxide and urea) blood pH the concentration of glucose in the blood the water potential of the blood the concentration of respiratory gases (carbon dioxide and oxygen) in the blood

Question 682

2.81 homeostatic mechanisms in mammals require

Answer 682

information to be transferred between different parts of the body

Question 683

2.81 what are the two communication systems in mammals that require information to be transferred to different parts of the body

Answer 683

the nervous system the endocrine system

Question 684

2.81 homeostasis is what

Answer 684

the control or regulation of the internal conditions of a cell or organisms

Question 685

2.81 examples of homeostasis of internal conditions

Answer 685

water content (of an individual cell or of the body fluids of an organism) temperature pH blood pressure blood glucose concentration

Question 686

2.81 why is it important for an organism to keep internal conditions within set limits

Answer 686

to ensure they stay healthy and maintain optimum conditions to allow the organism to function in response to internal and external changes

Question 687

2.81 if the internal conditions of homeostasis exceed the set limits

Answer 687

the organism may die

Question 688

2.81 homeostasis maintains optimal conditions for what

Answer 688

enzyme action and all cell functions

Question 689

2.81 homeostasis ensures

Answer 689

hat reactions in body cells can function and therefore the organism as a whole can live

Question 690

2.81 the core body temp of humans is kept close to

Answer 690

37 degrees celsius

Question 691

2.81 why core body temp of humans kept close to 37

Answer 691

a temperature change would stop essential enzymes from functioning optimally

Question 692

2.81 to keep the body temp at 37 the human body must be able to

Answer 692

make a coordinated response to any rise or fall in body temperature

Question 693

2.81 body temperature is monitored and controlled by what

Answer 693

the thermoregulatory centre in base of the brain as blood passes through it

Question 694

2.81 the thermoregulatory centre contains what

Answer 694

receptors that are sensitive to the temperature of the blood

Question 695

2.81 the skin also contains temperature receptors and

Answer 695

sends nervous impulses to the thermoregulatory centre the brain then coordinates a cooling or heating response depending on what is required

Question 696

2.81 water loss via the lungs - during breathing - or skin - during sweating - cannot

Answer 696

be controlled

Question 697

2.81 the volume of water lost in the production of urine

Answer 697

can be controlled by the kidneys

Question 698

2.81 water can be reabsorbed from the filtrate as it passes along the collecting ducts

Answer 698

if the water content of the blood is too high then less water is reabsorbed, if it is too low then more water is reabsorbed this causes either a large amount of dilute urine to be produced, or a small amount of concentrated urine a hormone called ADH controls this process

Question 699

2.82 a co-ordinated response requires

Answer 699

a stimulus, a receptor and an effector

Question 700

2.82 homeostasis is under what type of control

Answer 700

involuntary / automatic

Question 701

2.82 what does involuntary / automatic control mean

Answer 701

the brain stem (or non-conscious part of the brain) and the spinal cord are involved in maintaining homeostasis – you don’t consciously maintain your body temperature or blood glucose level

Question 702

2.82 automatic control systems involve

Answer 702

nervous responses or chemical responses e.g. hormones

Question 703

2.82 all control systems that carry out a coordinated response require what

Answer 703

a stimulus a receptor a coordination centre an effector

Question 704

2.82 what is the stimulus

Answer 704

a change in the environment e.g. a change in glucose levels in the blood, a change in body temperature etc

Question 705

2.82 what is the receptor

Answer 705

receptor cells that detect stimuli

Question 706

2.82 what is the coordination centre

Answer 706

the brain, spinal cord and pancreas, which receives and processes information from receptors

Question 707

2.82 what is an effector

Answer 707

a muscle or gland, which brings about responses to restore optimum levels

Question 708

2.82 a coordinated response such as what

Answer 708

stuff required when there is not enough water in the blood

Question 709

2.83 plants respond to what

Answer 709

stimuli

Question 710

2.83 plants need to be able to grow in response to certain

Answer 710

stimuli

Question 711

2.83 plants need to be able to grow in response to what

Answer 711

light

Question 712

2.83 plants need to be able to grow in response to

Answer 712

light or gravity

Question 713

2.83 why do plants grow in response to light

Answer 713

to ensure their leaves can absorb light for photosynthesis

Question 714

2.83 why do plants grow in response to gravity

Answer 714

to ensure that shoots grow upwards and roots grow downwards

Question 715

2.83 what are the directional growth responses made by plants - in response to light / gravity - known as

Answer 715

tropisms

Question 716

2.83 what are tropisms

Answer 716

the directional growth responses made by plants in response to light and gravity

Question 717

2.83 if growth is towards the stimulus in plants the tropism is

Answer 717

positive

Question 718

2.83 if growth is away from the stimulus in plants the tropism is

Answer 718

negative

Question 719

2.83 what does it mean if the tropism is positive

Answer 719

the growth is towards the stimulus

Question 720

2.83 what does it mean if the tropism is negative

Answer 720

the growth is away from the stimulus

Question 721

2.84 a response to light in a plant is

Answer 721

phototropism

Question 722

2.84 a response to gravity in a plant is

Answer 722

geotropism (or gravitropism)

Question 723

2.84 as the shoot grows upwards, away from gravity & towards light shoots show

Answer 723

a positive phototropic response and a negative geotropic response

Question 724

2.84 give an example of a positive phototropic response and a negative geotropic response

Answer 724

when a shoot grows upwards, away from gravity and towards the light - so leaves are able to absorb sunlight

Question 725

2.84 as roots grow downwards into the soil away from light and towards gravity shoots show

Answer 725

a negative phototropic response and a positive geotropic response

Question 726

2.84 give an example of a negative phototropic response and a positive geotropic response

Answer 726

when a shoot grows downwards, away from the light and into the soil, towards gravity - in order to anchor the plant and absorb water and minerals from the soil

Question 727

2.84 stimulus of light give the name of response positive response negative response

Answer 727

phototropism growth towards the light source - shoots growth away from the light source - roots

Question 728

2.84 stimulus of gravity give the name of response positive response negative response

Answer 728

geotropism growth towards source of gravity - roots growth away from source of gravity - shoots

Question 729

2.84 definition of phototropism

Answer 729

growth towards or away from the direction of the light source

Question 730

2.84 definition of geotropism

Answer 730

growth towards or away from the source of gravity

Question 731

2.85 plants produce what ? for growth responses

Answer 731

plant growth regulators (similar to hormones in animals)

Question 732

2.85 what are plant growth regulators called

Answer 732

auxins

Question 733

2.85 why do plants produce auxin

Answer 733

to coordinate and control directional growth responses such as phototropisms and geotropisms

Question 734

2.85 what is a plant growth regulator

Answer 734

auxin

Question 735

2.85 why do plants produce plant growth regulators

Answer 735

to coordinate and control directional growth responses such as phototropisms and geotropisms

Question 736

2.85 what is auxin

Answer 736

a plant growth regulator

Question 737

2.85 what coordinates & controls directional growth responses such as phototropisms and geotropisms

Answer 737

auxin

Question 738

2.85 auxin coordinates & controls directional growth response such as

Answer 738

phototropisms and geotropisms

Question 739

2.85 auxin is mostly made where

Answer 739

in the tips of growing shoots and then diffuses down into the region where cell division occurs

Question 740

2.85 why is the region behind the tip of a shoot important

Answer 740

it is the only region that is able to contribute to growth by cell division and cell elongation

Question 741

2.85 auxin stimulates the region behind the tip of the shoot to

Answer 741

elongate

Question 742

2.85 the more auxin there is

Answer 742

the faster the cells will elongate and grow

Question 743

2.85 if light shines around the tip of a shoot, auxin is distributed

Answer 743

evenly throughout

Question 744

2.85 if light shines around the tip of a shoot, auxin means the cells in the shoot grow

Answer 744

at the same rate

Question 745

2.85 if light shines predominantly on one side of a shoot, auxin is distributed

Answer 745

and concentrates on the shaded side

Question 746

2.85 if light shines predominantly on one side of a shoot, auxin means the cells in the shoot grow

Answer 746

and elongate on the shaded side, and grow faster than the cells on the sunny side

Question 747

2.85 unequal growth on either side of the shoot causes

Answer 747

the shoot to bend and grow in the direction of the light

Question 748

2.85 positive phototropism in plants shoots is a result of

Answer 748

auxin accumulating on the shaded side of a shoot

Question 749

2.85 what is better to write in relation to phototropism / geotropism instead of 'grows towards the light'

Answer 749

cell elongation

Question 750

2.86 there are two different control systems in humans that work together to do what

Answer 750

respond to stimuli

Question 751

2.86 what are the two different control systems that respond to stimuli

Answer 751

the nervous system the hormonal system - also known as the endocrine system

Question 752

2.86 changes in our external environment or in the internal environment of our bodies act as

Answer 752

stimuli

Question 753

2.86 the nervous and hormonal systems do what to stimuli

Answer 753

coordinate a suitable response to stimuli

Question 754

2.86 what allows us to coordinate and regulate body functions

Answer 754

our systems coordinating to make a suitable response to stimuli - external / internal environment

Question 755

2.86 the nervous system & endocrine / hormonal system allow us to do what

Answer 755

to coordinate and regulate body functions by making a suitable response to stimuli - external / internal environment

Question 756

2.86 information is sent through the nervous system as what

Answer 756

electrical impulses

Question 757

2.86 what are electrical impulss

Answer 757

electrical signals that pass along nerve cells known as neurones

Question 758

2.86 what are nerve cells known as in the nervous system

Answer 758

neurones

Question 759

2.86 impulses that travel along neurones travel at

Answer 759

very high speeds up to 100 metres per second

Question 760

2.86 what allows rapid responses to stimuli in the nervous system

Answer 760

the impulses travelling at very high speeds along neurones

Question 761

2.86 what is an example of a rapid response to stimuli

Answer 761

the withdrawal reflex which causes you to move your hand away fast when it touches a flame

Question 762

2.86 the nervous system coordinates the activities of what receptors

Answer 762

sensory receptors

Question 763

2.86 what are the three thing the nervous system coordinates activity for

Answer 763

sensory receptors, decision-making centres in the central nervous system and effectors such as muscles and glands

Question 764

2.86 the nervous system coordinates the activities of decision-making centres in what

Answer 764

the central nervous system

Question 765

2.86 the nervous system coordinates the activities of muscles and glands which are

Answer 765

effectors

Question 766

2.86 the nervous system is used to

Answer 766

control functions that need instant or very rapid responses

Question 767

2.86 information is sent through the endocrine system as

Answer 767

chemical substances known as hormones

Question 768

2.86 hormones are carried by what

Answer 768

the blood and therefore can circulate around the whole body

Question 769

2.86 hormones transmit information from one part of the organism to another and bring about what

Answer 769

a change - they provide a signal that triggers a response

Question 770

2.86 hormones alter what

Answer 770

they alter the activity of one or more specific target organs

Question 771

2.86 what are hormones used to control functions

Answer 771

that do not need instant responses

Question 772

2.86 hormones are produced by what

Answer 772

endocrine glands

Question 773

2.86 the endocrine glands that produce hormones in animals are collectively known as the

Answer 773

endocrine system

Question 774

2.86 what is a gland

Answer 774

a group of cells that produces and releases one or more substances (a process known as secretion

Question 775

2.86 comparison between nervous & endocrine system 1. made of 2. type of message 3. speed of action 4. duration of effect

Answer 775

1. N: nerves, brain & spinal cord E: glands 2. N: electrical E: chemical hormone 3. N: very fast E: slower 4. N: short - until the nerve impulses stops 4. E: long until the hormone is broken down in the body

Question 776

2.86 comparison between nervous & endocrine system made up of

Answer 776

N: nerves, brain & spinal cord E: glands

Question 777

2.86 comparison between nervous & endocrine system type of message

Answer 777

N: electrical E: chemical hormone

Question 778

2.86 comparison between nervous & endocrine system speed of action

Answer 778

N: very fast E: slower

Question 779

2.86 comparison between nervous & endocrine system duration of effect

Answer 779

N: short - until the nerve impulses stops E: long until the hormone is broken down in the body

Question 780

2.86 what are nerves

Answer 780

bundles of neurones

Question 781

2.87 what does the central nervous system consist of

Answer 781

the brain and spinal cord which is linked to the organs by nerves

Question 782

2.87 the human nervous system consists of

Answer 782

CNS - the central nervous system, the brain an spinal cord PNS - the peripheral nervous system, all of the nerves in the body

Question 783

2.87 information is sent through the nervous system as

Answer 783

electrical impulses - electrical signals that pass along nerve cells known as neurones

Question 784

2.87 a bundle of neurones is known as what

Answer 784

a nerve

Question 785

2.87 the nerves spread out from the central nervous system to

Answer 785

all other regions of the body and to all the sense organs

Question 786

2.87 the CNS acts as

Answer 786

a central coordinating centre for the impulses that come in from or are sent out to any part of the body

Question 787

2.88 stimulation of receptors in the sense organs send what

Answer 787

electrical impulses along nerves into and out of the central nervous system resulting in rapid responses

Question 788

2.88 what results in rapid responses

Answer 788

stimulation of receptors in the sense organs send electrical impulses along nerves into and out of the central nervous system

Question 789

2.88 a stimulation of receptors in the sense organs sends what

Answer 789

electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses

Question 790

2.88 what is the pathway through the nervous system

Answer 790

stimulus → sensory neurone → relay neurone → motor neurone → effector → response

Question 791

2.88 what is a stimulus received by

Answer 791

a stimulus is received by a sensory (receptor) neurone

Question 792

2.88 what are most receptors specialised to

Answer 792

most receptors are specialised to detect particular stimuli

Question 793

2.88 what happens when a receptor is stimulated

Answer 793

it produces electrical impulses

Question 794

2.88 where do the impulses travel to along the sensory neurone

Answer 794

to the central nervous system the coordinator is either the brain or the spinal cord

Question 795

2.88 in the central nervous system the impulses are passed on to what

Answer 795

a relay neurone

Question 796

2.88 the relay neurone links to what

Answer 796

a motor neurone

Question 797

2.88 when the relay neurone links to a motor neurone the impulses travel along it until

Answer 797

they reach the effector

Question 798

2.88 what is the effector

Answer 798

its what carries out the response

Question 799

2.88 what may an effector be

Answer 799

a muscle or gland

Question 800

2.88 describe the nerve pathway from stimulus to response

Answer 800

- stimulus - is detected by receptor - sensory neurone - relay neurone - CNS - motor neurone - impulses are sent along the sensory neurone, then the relay neurone and then the motor neurone - the impulses received by effector - response

Question 801

2.89 neurones do not do what

Answer 801

they do not go into direct contact with eachother

Question 802

2.89 what are dendrites

Answer 802

branched nerve fibres which receive nerve impulses and pass them towards a cell body

Question 803

2.89 the dendrites of two neurones meet to make what

Answer 803

to make a connection between the neurones

Question 804

2.89 when two dendrites meet what is formed

Answer 804

a junction known as a synapse

Question 805

2.89 what is a synapse

Answer 805

where the axon of one neurone connects with the dendrite of another or an effector they help coordinate activities and are unidirectional

Question 806

2.8 what is an axon

Answer 806

a single nerve fibre that carries nerve impulses away from a cell body

Question 807

2.89 at a synapse there is what

Answer 807

a very small gap between the neurones

Question 808

2.89 what is the gap between neurones called

Answer 808

the synaptic cleft or synaptic gap

Question 809

2.89 electrical impulses cannot what

Answer 809

travel directly from one neurone to the next due to the synaptic gap

Question 810

2.89 can electrical impulses travel directly from one neurone to the next

Answer 810

no due to the synaptic gap

Question 811

2.89 electricity can/cannot do what with the synaptic gap

Answer 811

electricity cannot jump the gap

Question 812

2.89 for electrical impulses to transfer

Answer 812

the electrical signal is briefly converted to a chemical signal that can cross the synaptic gap

Question 813

2.89 what can pass in the synaptic gap

Answer 813

a chemical signal known as neurotransmitters

Question 814

2.89 to pass the synaptic gap the electrical signal is converted to what

Answer 814

a chemical signal

Question 815

2.89 what is the chemical signalling molecules called

Answer 815

neurotransmitters

Question 816

2.89 what are neurotransmitters

Answer 816

chemical signalling molecules that are used to transfer the signal between neurones at a synapse that can cross the synaptic gap

Question 817

2.89 what are the chemical signalling molecules used for

Answer 817

to transfer the signal between neurones at a synapse

Question 818

2.89 when the neurotransmitters meet the neurone on the opposite side the signal is converted back

Answer 818

back into an electrical impulse which can then pass along the neurone

Question 819

2.89 the electrical impulse travels along the

Answer 819

axon of the first neurone

Question 820

2.89 what is the presynaptic neurone

Answer 820

the axon of the first neurone

Question 821

2.89 when the electrical impulse travels along the axon of the first neurone / presynaptic neurone what does it trigger

Answer 821

it triggers the end of the presynaptic neurone to release chemicals called neurotransmitters from vesicles

Question 822

2.89 what do vesicles fuse with

Answer 822

the presynaptic membrane, releasing their contents into the synaptic gap

Question 823

2.89 the neurotransmitters diffuse across the synaptic gap and bind with what

Answer 823

bind with receptor molecules on the membrane of the second neurone known as the postsynaptic membrane

Question 824

2.89 what is the postsynaptic membrane

Answer 824

the membrane on the second neurone

Question 825

2.89 after the neurotransmitters diffuse across the synaptic gap and bind with receptor molecules on the postsynaptic membrane what is stimualted

Answer 825

it stimulates the second neurone to generate an electrical impulse which then travels down the second axon

Question 826

2.89 the neurotransmitters are destroyed to prevent what

Answer 826

continued stimulation of the second neurone - otherwise the neurotransmitters would cause repeated impulses to be sent

Question 827

2.89 to prevent continued stimulation of the impulses,w hat happens to the neurotransmitters

Answer 827

they are destroyed

Question 828

2.89 synapses ensure impulses can what

Answer 828

only travel in one direction

Question 829

2.89 pathway of how an impulse is passed on at a synapse

Answer 829

1. an impulse arrives at the end of the presynaptic neurone 2. vesicles move towards & fuse with the presynaptic membrane this releases neurotransmitters into the synaptic gap 3. the neurotransmitters diffuse across the synaptic gap - down a concentration gradient 4. neurotransmitters attach the to receptors on the postsynaptic membrane 5. this triggers an impulse which travels along the postsynaptic neurone 6. the neurotransmitters are recycled or destroyed once an impulse is sent

Question 830

2.89 neurotransmitters move by what

Answer 830

diffusion which requires a concentration gradient & is a passive process

Question 831

2.89 receptors that are complementary in shape to neurotransmitters are located where

Answer 831

on the postsynaptic neurone

Question 832

2.89 drugs such as heroin, ecstasy & cocaine can bind to neurotransmitter receptors that what

Answer 832

triggers impulses in different regions of the brain

Question 833

2.90 what is a reflex response also known as

Answer 833

an involuntary response

Question 834

2.90 a reflex response does not involve what

Answer 834

the conscious part of the brain as the coordinator of the reaction

Question 835

2.90 awareness of a response happens when

Answer 835

after the response has been carried out

Question 836

2.90 responses are what

Answer 836

automatic and rapid

Question 837

2.90 what helps minimise damage to the body and aids survival

Answer 837

responses are automatic and rapid

Question 838

2.90 why are automatic and rapid responses helpful

Answer 838

they minimise danger to the body and aid survival

Question 839

2.90 name examples of reflex responses that help us avoid serious injury

Answer 839

pain-withdrawal, blinking, and coughing

Question 840

2.90 the reflex arc is what

Answer 840

the pathway of reflex response

Question 841

2.90 reflex arc pathway

Answer 841

stimulus -> receptor -> sensory neurone -> intermediate relay neurone -> motor neurone -> effector -> response

Question 842

2.90 what is the pathway taken by electrical impulses as they travel along neurones

Answer 842

stimulus -> receptor -> sensory neurone -> intermediate relay neurone -> motor neurone -> effector -> response

Question 843

2.90 give the example of the reflex response when someone stands on a pin

Answer 843

- the pin (the stimulus) is detected by a - (pain/pressure/touch) receptor in the skin on the person's foot - a sensory neurone sends electrical impulses to the spinal cord (the coordinator) - an electrical impulse is passed to a relay neurone in the spinal cord (part of the CNS) - a relay neurone synapses with a motor neurone - a motor neurone carries an impulse to a muscle in the leg (the effector) - when stimulated by the motor neurone, the muscle will contract and pull the foot up and away from the sharp object (the response)

Question 844

2.91 the eye is what

Answer 844

a highly specialised sense organ containing receptor cells that allow us to detect the stimulus of light

Question 845

2.91 the retina of the eye contains what

Answer 845

two types of receptor cells

Question 846

2.91 what are two types of receptor cells in the retina

Answer 846

rods and cones

Question 847

2.91 which receptor cells in the eye are sensitive to light

Answer 847

the rods

Question 848

2.91 which receptor cells can detect colour

Answer 848

the cones

Question 849

2.91 the eye is a sense organ that contains what

Answer 849

light receptor cells

Question 850

2.91 what type of organ is the eye

Answer 850

a sense organ

Question 851

2.91 what are the structures in the eye

Answer 851

cornea iris lens retina optic nerve pupil conjunctiva ciliary muscle suspensory ligaments sclera fovea blind spot

Question 852

2.91 describe the structure of the cornea

Answer 852

a transparent lens that refracts light as it enters the eye

Question 853

2.91 describe the structure of the iris

Answer 853

controls how much light enters the pupil

Question 854

2.91 describe the structure of the lens

Answer 854

transparent disc that can change shape to focus light onto the retina

Question 855

2.91 describe the structure of the retina

Answer 855

contains light receptor cells – rods (detect light intensity) and cones (detect colour)

Question 856

2.91 describe the structure of the optic nerve

Answer 856

sensory neuron that carries impulses between the eye and the brain

Question 857

2.91 describe the structure of the pupil

Answer 857

hole that allows light to enter the eye

Question 858

2.91 describe the structure of the conjunctiva

Answer 858

a clear membrane that covers the white of the eye and the inside of the eyelids; it lubricates the eye and provides protection from external irritants

Question 859

2.91 describe the structure of the ciliary muscle

Answer 859

a ring of muscle that contracts and relaxes to change the shape of the lens

Question 860

2.91 describe the structure of the suspensory ligaments

Answer 860

ligaments that connect the ciliary muscle to the lens

Question 861

2.91 describe the structure of the sclera

Answer 861

the strong outer wall of the eyeball that helps to keep the eye in shape and provides a place of attachment for the muscles that move the eye

Question 862

2.91 describe the structure of the fovea

Answer 862

a region of the retina with the highest density of cones (colour detecting cells) where the eye sees particularly good detail

Question 863

2.91 describe the structure of the blind spot

Answer 863

the point at which the optic nerve leaves the eye, where there are no receptor cells

Question 864

2.92 what is the function of the eye

Answer 864

focusing on near and distant objects

Question 865

2.92 the way the lens brings about fine focusing is called what

Answer 865

accommodation

Question 866

2.92 what is accommodation

Answer 866

the way the lens brings about fine focusing

Question 867

2.92 what shape and texture is the lens

Answer 867

it is elastic and its shape can be changed

Question 868

2.92 how can the lens shape be changed

Answer 868

the suspensory ligaments attached to it become tight or loose

Question 869

2.92 how does the lens change shape

Answer 869

the changes are brought about by the contraction or relaxation of the ciliary muscles

Question 870

2.92 what happens when the ciliary muscles contract or relax

Answer 870

the lens changes shape

Question 871

2.92 what happens in the eye when an object is close up

Answer 871

the ciliary muscles contract (the ring of muscle decreases in diameter) this causes the suspensory ligaments to loosen this stops the suspensory ligaments from pulling on the lens, which allows the lens to become fatter light is refracted more

Question 872

2.92 what is the result when an object is close to the eye

Answer 872

light is refracted more by lens to focus on near objects

Question 873

2.92 what happens in the eye when an object is far away

Answer 873

the ciliary muscles relax (the ring of muscle increases in diameter) this causes the suspensory ligaments to tighten the suspensory ligaments pull on the lens, causing it to become thinner light is refracted less

Question 874

2.92 what is the result when an object is far away from the eye

Answer 874

light is refracted less allowing the eye to focus on a distant object

Question 875

2.92 what happens to the ciliary muscles, suspensory ligaments, lens and light refraction when the eye focuses on near objects

Answer 875

ciliary muscles: contracted suspensory ligaments: loose lens: fatter light refraction: more

Question 876

2.92 what happens to the ciliary muscles, suspensory ligaments, lens and light refraction when the eye focuses on distant objects

Answer 876

ciliary muscles: relaxed suspensory ligaments: tight lens: thinner light refraction: less

Question 877

2.92 the suspensory ligaments are not muscles so you cannot say they contract or relax, instead what do you say

Answer 877

tighten or loosen

Question 878

2.92 the pupil reflex is what

Answer 878

a reflex action

Question 879

2.92 why does the pupil reflex

Answer 879

to protect the retina from damage

Question 880

2.92 to protect the retina from damage the pupil does what

Answer 880

the pupil has a reflex action called the pupil reflex

Question 881

2.92 what happens to the pupil in dim light

Answer 881

the pupil dilates (widens) in order to allow as much light into the eye as possible to improve vision

Question 882

2.92 what happens to the pupil in bright light

Answer 882

the pupil constricts (narrows) in order to prevent too much light from entering the eye and damaging the retina

Question 883

2.92 in what type of light does the pupil dilate

Answer 883

dim light

Question 884

2.92 in what type of light does the pupil constrict

Answer 884

bright light

Question 885

2.92 what happens to the radial muscles of the iris, the circular muscles of the iris and the pupil in dim light

Answer 885

radial muscles of the iris: contracted circular muscles of the iris: relaxed pupil is: dilated - light enters eye

Question 886

2.92 what happens to the radial muscles of the iris, the circular muscles of the iris and the pupil in bright light

Answer 886

radial muscles of the iris: relaxed circular muscles of the iris: contracted pupil is: constricted - less light enters eye

Question 887

2.92 explain the eye in a dark environment

Answer 887

photoreceptors detect the change in environment to being dark radial muscles contract circular muscles relax pupil dilates more light enters the eye

Question 888

explain the pupil reflex in regard to bright light

Answer 888

radial muscles: relaxed circular muscles: contracted pupil size: narrow light entering eye: less

Question 889

2.92 explain the eye in a bright environment

Answer 889

photoreceptors detect the change in environment to being bright radial muscles relax circular muscles contract pupil constricts less light enters the eye

Question 890

explain the pupil reflex in regard to dim light

Answer 890

radial muscles: contracted circular muscles: relaxed pupil size: wide light entering eye: more

Question 891

2.93 the skin is what

Answer 891

our largest sense organ

Question 892

2.93 what does the skin contain that lets us detect external stimuli

Answer 892

many different receptors

Question 893

2.93 why does the skin contain many different receptors

Answer 893

it allows us to detect various external stimuli including touch, pressure, pain, heat and cold

Question 894

2.93 give examples of external stimuli our skin can detect

Answer 894

touch, pressure, pain, heat and cold

Question 895

2.93 structures in the skin also do what

Answer 895

they play an important role in regulating body temperature - an example of homeostasis

Question 896

2.93 mention the structures in the skin that can increase or reduce heat loss to the surroundings

Answer 896

muscles fatty tissue arteriole sensory neurone sweat gland dermis capillaries muscle epidermis free nerve ending sweat pore hair check save my exams diagram - skin and temperature

Question 897

2.93 what are the cooling mechanisms in humans - non detailed

Answer 897

vasodilation of skin capillaries sweating flattening of hairs

Question 898

2.93 what are the cooling mechanisms in humans - detailed

Answer 898

vasodilation of skin capillaries heat exchange (both during warming and cooling) occurs at the body's surface as this is where the blood comes into closest proximity to the environment one way to increase heat loss is to supply the capillaries in the skin with a greater volume of blood, which then loses heat to the environment via radiation arterioles (small vessels that connect arteries to capillaries) have muscles in their walls that can relax or contract to allow more or less blood to flow through them during vasodilation, these muscles relax, causing the arterioles near the skin to dilate (get wider) and allowing more blood to flow through capillaries sweating sweat is secreted by sweat glands this cools the skin by evaporation which uses heat energy from the body to convert liquid water into water vapour flattening of hairs the hair erector muscles in the skin relax, causing hairs to lie flat this stops them from forming an insulating layer by trapping air and allows air to circulate over the skin and allows heat to leave by radiation

Question 899

2.93 describe the vasodilation of skin capillaries for the cooling mechanism in humans

Answer 899

heat exchange occurs at the body's surface as this is where the blood is closest proximity to the environment one way to increase heat loss is to supply the capillaries in the skin with a greater volume of blood which then loses heat to the environment via radiation arterioles have muscles in their walls that can relax causing the arterioles near the skin to dilate and allows more blood to flow through capillaries

Question 900

2.93 describe sweating for the cooling mechanism in humans

Answer 900

sweat is secreted by sweat glands this cools the skin by evaporation which uses heat energy from the body to convert liquid water into water vapour

Question 901

2.93 describe the flattening of hairs for the cooling mechanism in humans

Answer 901

the hair erector muscles in the skin relax, causing hairs to lie flat this stops them from forming an insulating layer by trapping air and allows air to circulate over the skin and allows heat to leave by radiation

Question 902

2.93 describe the responses in the skin when the body temperature is too high and needs to decrease

Answer 902

sweat glands excrete sweat which cools the skin as it evaporates hair erector muscles will relax vessels dilate to increase blood flow to the skin

Question 903

2.93 what are the warming mechanisms in humans - non detailed

Answer 903

vasoconstriction of skin capillaries shivering erection of hairs

Question 904

2.93 what are the heating mechanisms in humans - detailed

Answer 904

vasoconstriction of skin capillaries one way to decrease heat loss is to supply the capillaries in the skin with a smaller volume of blood, minimising the loss of heat to the environment via radiation during vasoconstriction, the muscles in the arteriole walls contract, causing the arterioles near the skin to constrict (get smaller) and allowing less blood to flow through capillaries vasoconstriction is not, strictly speaking, a 'warming' mechanism as it does not raise the temperature of the blood but instead reduces heat loss from the blood as it flows through the skin shivering this is a reflex action in response to a decrease in core body temperature muscles contract in a rapid and regular manner the exothermic metabolic reactions required to power this shivering generate sufficient heat to warm the blood and raise the core body temperature erection of hairs the hair erector muscles in the skin contract, causing hairs to stand on end this forms an insulating layer over the skin's surface by trapping air between the hairs and stops heat from being lost by radiation

Question 905

2.93 describe the vasoconstriction of skin capillaries for the heating mechanism in humans

Answer 905

one way to decrease heat loss is to supply the capillaries in the skin with a smaller volume of blood - this minimises the heat loss to the environment via radiation

Question 906

2.93 describe shivering for the heating mechanism in humans

Answer 906

this is a reflex action in response to a decrease in core body temperature muscles contract in a rapid & regular manner the exothermic metabolic reactions required to power this shivering generate sufficient heat to warm the blood and raise the core body temperature

Question 907

2.93 describe the erection of hairs for the heating mechanism in humans

Answer 907

the hair erector muscles in the skin contract this causes the hairs to stand on end this forms an insulating layer over the skins surface by trapping air between the hairs and stops heat from being lose by radiation

Question 908

2.93 describe the responses in the skin when the body temperature is too low and needs to increase

Answer 908

the hair stands upright trapping the air around the skin trapped air is an excellent insulator hair erector muscles will contract vessels constrict reducing blood flow to the skin remember - heat energy transfer always occurs from hotter regions to cooler regions radiation is heat energy transfer by electromagnetic radiation conduction and convection are the other two types

Question 909

2.93 what is the core body temperature of humans kept close to

Answer 909

37 degrees celsius

Question 910

2.93 why is the core body temperature of humans kept close to 37 degrees celcius

Answer 910

it is tightly controlled as a change in core body temperature of more than 2 degrees celsius can be fatal

Question 911

2.93 to keep the body at a core body temperature the human body must be able to do what

Answer 911

make a coordinated response to any rise or fall in body temperature

Question 912

2.93 temperature recepters are also known as what

Answer 912

thermoreceptors

Question 913

2.93 what are thermoreceptors also known as

Answer 913

temperature receptors

Question 914

2.93 where are the temperature receptors / thermoreceptors found

Answer 914

in the skin and hypothalamus

Question 915

2.93 what can detect minute changes in body temperature

Answer 915

temperature receptors or thermoreceptors

Question 916

2.93 what do the temperature receptors / thermoreceptors do

Answer 916

they detect minute changes in body temperature

Question 917

2.93 the brain does what when there is a change in body temperature

Answer 917

the brain coordinates a cooling or heating response depending on what is required

Question 918

2.93 temperature regulation is an example of what

Answer 918

homeostasis

Question 919

2.93 what happens when there is an increase in body temperature

Answer 919

thermoreceptors in the hypothalamus and skin can detect change this leads to increased sweating, vasodilation & hairs lie flat against the skin this leads to a decrease in body temperature

Question 920

2.93 what happens when there is an decrease in body temperature

Answer 920

thermoreceptors in the hypothalamus and skin detect change this leads to shivering, vasoconstriction & skin hairs erect this leads to an increase in body temperature

Question 921

2.94 what is a hormone

Answer 921

it is a chemical substance produced by a gland and carried by the blood which alters the activity of one or more specific target organs

Question 922

2.94 what do hormones do

Answer 922

they are chemicals that transmit information from one part of the organism to another and bring about a change

Question 923

2.94 what are the important hormones

Answer 923

adrenaline insulin testosterone progesterone oestrogen

Question 924

2.94 what is adrenaline known as

Answer 924

the fight or flight hormone as it is produced in situations where the body may be in danger

Question 925

2.94 what does adrenaline cause

Answer 925

a range of different things to happen in the body, all designed to prepare it for movement

Question 926

2.94 what does adrenaline do to the body - non-detailed

Answer 926

an increase in heart & breathing rate diverts blood flow towards muscles dilation of the blood vessels inside muscles breaks down stored glycogen into glucose

Question 927

2.94 what does adrenaline do to the body - detailed

Answer 927

increase in heart rate and breathing rate - ensures glucose and oxygen can be delivered to muscle cells (and carbon dioxide can be taken away from muscles cells) at a faster rate diverting blood flow towards muscles and away from non-essential parts of the body such as the alimentary canal - ensures an increased supply of the reactants of respiration (glucose and oxygen) dilation of the blood vessels inside muscles - ensures more blood can circulate through them (again, supplying more glucose and oxygen) breaking down of stored glycogen to glucose in the liver and muscle cells, with glucose released by the liver being transported to active muscle cells - ensures a higher blood glucose concentration for increased respiration in muscle cells (providing greater energy for movement)

Question 928

2.94 blood glucose concentration is an example of what

Answer 928

homeostasis

Question 929

2.94 too high a level of glucose in the blood can lead to what

Answer 929

the cells of the body losing water by osmosis which can be dangerous

Question 930

2.94 too low of glucose in the blood can lead to what

Answer 930

the brain receiving insufficient glucose for respiration potentially leading to a coma or even death

Question 931

2.94 what works together to control blood glucose levels

Answer 931

the pancreas and liver

Question 932

2.94 the pancreas and liver work together to do what

Answer 932

control blood glucose level

Question 933

2.94 what happens if the blood glucose concentration gets too high

Answer 933

cells in the pancreas detect the increased blood glucose levels the pancreas produces the hormone insulin, secreting it into the blood insulin stimulates muscles and the liver to take up glucose from the bloodstream and store it as glycogen (a polymer of glucose) this reduces the concentration of glucose in the blood back to normal levels, at which point the pancreas stops secreting insulin

Question 934

2.94 to maintain blood glucose levels the pancreas acts as what and does what

Answer 934

the pancreas acts as an endocrine gland (making and secreting hormones into the bloodstream)

Question 935

2.94 explain the regulation of blood glucose levels

Answer 935

- blood glucose levels rise - pancreas releases insulin - insulin stimulates uptake of glucose into the liver - liver stores excess glucose as glycogen - blood glucose levels reduce

Question 936

2.94 where is testosterone produced

Answer 936

in the male testes

Question 937

2.94 what is testosterone responsible for

Answer 937

the development of secondary sexual characteristics in males

Question 938

2.94 what is responsible for the development of secondary sexual characteristics in males

Answer 938

testosterone

Question 939

2.94 where is progesterone produced

Answer 939

in the female ovaries

Question 940

2.94 what is progesterone responsible for

Answer 940

maintaining the uterine lining during pregnancy

Question 941

2.94 what is responsible for for maintaining the uterine lining during pregnancy

Answer 941

progesterone

Question 942

2.94 where is oestrogen produced

Answer 942

in the female ovaries

Question 943

2.94 what is oestrogen responsible for

Answer 943

for the development of secondary sexual characteristics in females and regulating the menstrual cycle

Question 944

2.94 what is responsible for the development of secondary sexual characteristics in females and regulating the menstrual cycle

Answer 944

oestrogen

Question 945

2.94 adrenaline source, role and effect

Answer 945

adrenal gland readies the body for a 'fight or flight' response increases heart and breathing rate

Question 946

2.94 where is adrenaline produced

Answer 946

adrenal gland

Question 947

2.94 insulin source, role and effect

Answer 947

pancreas lowers blood glucose levels causes excess glucose in the blood to be taken up by the muscles and liver and converted into glycogen for storage

Question 948

2.94 testosterone source, role and effect

Answer 948

testes main sex hormone in males development of male reproductive organs and secondary characteristics

Question 949

2.94 progesterone source, role and effect

Answer 949

ovaries maintains pregnancy maintains the uterus lining to cushion the fertilised egg and allow it to develop

Question 950

2.94 oestrogen source, role and effect

Answer 950

ovaries main sex hormone in females development of female secondary sexual characteristics and regulation of the menstrual cycle

Question 951

2.95B what are the three advanced hormones you need to know

Answer 951

ADH antidiuretic hormone FSH follicle-stimulating hormone LH luteinising hormone

Question 952

2.95B what does ADH stand for

Answer 952

antidiuretic hormone

Question 953

2.95B what does FSH stand for

Answer 953

follicle-stimulating hormone

Question 954

2.95B what does LH stand for

Answer 954

luteinising hormone

Question 955

2.95B ADH if the water content of the blood falls below a certain level

Answer 955

the blood is too concentrated receptors detect this and stimulate the pituitary gland to release more ADH this causes the collecting ducts of the nephrons to become more permeable to water this leads to more water being reabsorbed from the collecting ducts the kidneys produce a smaller volume of urine that is more concentrated (contains less water)

Question 956

2.95B ADH if the water content of the blood rises above a certain level

Answer 956

the blood is too dilute receptors detect this and stimulate the pituitary gland to release less ADH this causes the collecting ducts of the nephrons to become less permeable to water this leads to less water being reabsorbed from the collecting ducts the kidneys produce a larger volume of urine that is less concentrated (contains more water)

Question 957

2.95B ADH source, role and effect

Answer 957

pituitary gland controlling the water content of the blood increases the permeability of the collecting ducts in the kidneys to water, increasing the reabsorption of water back into the blood

Question 958

2.95B FSH source, role and effect

Answer 958

pituitary gland causes ovary to develop a mature egg cell stimulates the development of egg cells in the ovary and the release of oestrogen

Question 959

2.95B LH source, role and effect

Answer 959

pituitary gland causes ovary to release a mature egg cell stimulates the release of an egg cell from the ovary (ovulation) and the release of progesterone