2. Structures And Functions In Living Organisms Flashcards

Question

Why does an increase in temperature affect the rate of reaction !?

Answer 1

. This is because the higher temperature gives the enzymes and substrates MORE KINETIC ENERGY. They move faster and COLLIDE MORE OFTEN, so you get more reactions per second.

Answer 2

. You can use any enzyme to investigate the effect of temperature, this experiment studies the effect temperature has on AMYLASE . Amylase digests starch. - mix 10cm*3 of 10% starch suspension and 5cm*3 of 5% amylase in a boiling tube and heat in a water bath. - every minute take one drop of this mixture and add it to one drop of iodine solution in the spotting tile. - when digestion is complete and no starch is present, iodine will stay orange 🟧 (rather than turning blue black🟦⬛️) - repeat using different water bath temperatures

Answer 3

. The pH inside cells is neutral (pH 7) and most enzymes work best at this pH. Others work at different pH values in specialised parts of the body. . If the PH of the environment CHANGES it can affect the shape of the enzyme. The ACTIVE SITE CHANGES SHAPE so it is no longer complementary to the substrate. The enzyme is DENATURED and the reaction can no longer occur.

Answer 4

. You can use any enzyme to investigate the effect of pH . Potato contains the enzyme catalase which breaks down hydrogen peroxide, forming water and oxygen gas. -Add 10 potato disks (1cm thick, cut with a cork borer) to 20cm*3 catalase and measure the volume of gas produced in 5 minutes -the pH can be altered by adding different volumes of a weak alkali (e.g. sodium carbonate) or a weak acid (e.g. ethanoic acid) - use universal indicator paper to determine the pH of the solution each time

Answer 5

. All animals and plants

Answer 6

Glucose + oxygen➡️Carbon dioxide + water

Answer 7

. ATP provides cells with ENERGY

Answer 8

. ANAEROBIC Respiration

Answer 9

. As we use fungi such as yeast in bread and alcohol production. In both processes, we supply glucose and keep the yeast in low oxygen conditions so the cells can respire anaerobically. The carbon dioxide produced forms bubbles in bread dough and the ethanol provides the alcohol content in beer and wine.

Answer 10

. When investigating respiration we want to show that only living things respire. . To do this we use a CONTROL experiment.- identical to original without the independent variable - GERMINATING PEAS: As the peas start to grow they respire, releasing heat. The thermos flask is insulated, so heat isn’t transferred to the surroundings and we can measure the change in temperature. We only see a temperature rise in thermos A, as the peas in thermos B are dead. In both thermos flasks the peas are soaked in Milton Solution (bleach). This kills any bacteria We could also use gas delivery tubes to collect any gas produced. The gas can then be BUBBLES THROUGH LIMEWATER. The gas from flask A only would turn the limewater CLOUDY - this shows that CARBON DIOXIDE IS PRODUCED

Answer 11

. HYDROGEN CARBONATE INDICATOR AND INSECTS: - this indicator is red, but turns yellow when carbon dioxide concentration increases. - carbon dioxide reacts with water to form a weak acid

Answer 12

. Thermos flasks x2 . Thermometers x2 . Cotton wool plugs x2 . Peas seed in Milton solution . DEAD pea seed in Milton solution

Answer 13

. Test tubes x2 . Tightly fitting bung x2 . Hydrogen carbonate indicator . Insect . Support

Answer 14

. Carbon Dioxide

Answer 15

. In Respiring cells

Answer 16

. Respiration

Answer 17

. Lungs via blood plasma

Answer 18

. Liver cells

Answer 19

. Via the breakdown of amino acids

Answer 20

. Kidneys + skin

Answer 21

. They are structures that filter blood

Answer 22

. Millions

Answer 23

. The kidney filters the blood and removes any excess materials and passes them onto the bladder to be excreted

Answer 24

. Cortex (around the outside, lighter colour) . Medulla (middle, triangle shaped) . Pelvis (centre, yellowy🟨)

Answer 25

. Ultrafiltration

Answer 26

. The diameter of the [EFFERENT ARTERIOLE] at the exit of the [GLOMERULUS] is smaller than the diameter of the [AFFERENT ARTERIOLE] at the entrance. This creates a build-up of pressure in the capillaries forming the glomerulus.

Answer 27

. This pressure forces SMALL molecules such as UREA, GLUCOSE, AMINO ACIDS and salts out of the capillaries of the GLOMERULUS and into the BOWMAN’S CAPSULE. This forms the GLOMERULAR FILTRATE

Answer 28

. Larger molecules like PROTEINS or RED BLOOD CELLS are TOO BIG to fit across the capillary walls and therefore stay in the BLOOD

Answer 29

. The BASEMENT MEMBRANE surrounding the capillaries controls which molecules can pass onto the bowman’s capsule

Answer 30

. The capillaries of the glomerulus have gaps between the cells

Answer 31

. The filtrate travels to the PROXIMAL CONVOLUTED TUBULE (PCT). However it contains a lot of useful materials such as GLUCOSE which would be wasted unless they were recovered

Answer 32

. There are SPECIALISED cells within the walls of the PCT. These move the useful materials back into the BLOOD STREAM. Initially molecules will move by DIFFUSION, but some substances are also moved against a concentration gradient using ATP. This is called ACTIVE TRANSPORT.

Answer 33

. ALL of the glucose and amino acids are reabsorbed along with some salts and 80% of the water

Answer 34

. They have a FOLDED MEMBRANE to increase surface area . They have MANY MITOCHONDRIA to provide ATP for active transport

Answer 35

. 80% of water is reabsorbed in the PCT

Answer 36

. The loop of Henle concentrates the urine by transporting salt into the blood by ACTIVE TRANSPORT. This causes water to diffuse into the blood by OSMOSIS

Answer 37

. If you have lost a lot of water through sweating or perhaps haven’t taken in any your body will try to reabsorb as much water from the filtrate as it can. This makes the urine very concentrated, lower vol. of water so darker colour.

Answer 38

. Osmoregulation is when the COLLECTING DUCT responds to the hormone ADH to vary how much water is reabsorbed

Answer 39

Kidney➡️Ureter➡️Bladder➡️Urethra

Answer 40

. Water . Urea . Ions

Answer 41

. Organisms are able to respond to changes in their environment and make a coordinated response

Answer 42

. Animals and Humans have two organ systems to do this: - the nervous system - the endocrine system

Answer 43

. Yes, for example they can respond to the direction of light and grow towards it (phototropism) etc.

Answer 44

. A stimulus . A receptor . An effector

Answer 45

. The link is made by the nervous (and) or the endocrine system

Answer 46

. The CNS consists of the brain and the spinal chord - and is linked to sense organs by nerves

Answer 47

. The CNS coordinates all of the nervous responses such as moving or reflexes

Answer 48

. The peripheral nervous system contains all of the other nerves which send impulses to all the effectors

Answer 49

. Homeostasis is the maintenance of a constant internal environment

Answer 50

. Body water content . Body temperature . Blood sugar level

Answer 51

. The ENDOCRINE systems uses proteins, called HORMONES, that are released into the blood stream by GLANDS and target specific cells in the body

Answer 52

. IMPULSES from receptors pass along SENSORY NEURONES until they reach the brain and spinal chord (CENTRAL NERVOUS SYSTEM). Impulses pass to RELAY NEURONES in the CNS. The impulse is then passed to effectors (muscles or glands) along MOTOR NEURONES

Answer 53

. Slow (except adrenaline)

Answer 54

. Chemical message

Answer 55

. Via the blood- dissolved in the plasma

Answer 56

. only target cells respond even though the message is sent all over the body

Answer 57

. It controls long term processes such as reproduction and growth

Answer 58

. Electrical impulses

Answer 59

. Along neurones

Answer 60

. The message is sent directly to a muscle or a gland- not all over the body

Answer 61

. Used when a fast response is needed

Answer 62

. An electrical impulse travels along an axon . This triggers the nerve-ending of a neutron to release CHEMICAL MESSENGERS called neurotransmitters . These chemicals DIFFUSE across the synapse and bind with receptor molecules on the membrane of the next neuron

Answer 63

. Two neurones do not make direct contact. Where they meet, there is a very small gap called a synapse

Answer 64

. Reflex actions are AUTOMATED actions which DO NOT involve the BRAIN

Answer 65

. They are very fast actions

Answer 66

. Sensory neurone . Relay neurone . Motor neurone

Answer 67

. … A reflex arc

Answer 68

. The receptors detect the STIMULUS (change in temperature) and send an IMPULSE along the SENSORY NEURONE

Answer 69

. The sensory neurone passes the impulse to the SPINAL CHORD to a RELAY neurone. ( the gaps between neurones is called a synapse)

Answer 70

. The relay neurone passes the impulse through the spinal chord to a MOTOR NEURONE

Answer 71

. The motor neurone causes the effector (in this case arm muscles) to contract and move the arm away from the STIMULUS (hot object)

Answer 72

. The eye is a SENSORY organ which detects light and sends an IMPULSE to the brain which converts that information into an image which is what you “see”.

Answer 73

. The cornea is a curved transparent disc at the front of the eye. Does most of the focusing

Answer 74

. A circular opening who’s size is controlled by the iris (the coloured part of the eye)

Answer 75

. A ring of muscles with a hole in the middle (pupil). The iris controls how much light enters the eye

Answer 76

. The lens is soft, flexible and transparent. It’s shape can be changed to fine tune the focusing of light onto the retina

Answer 77

. A ring of muscles at the edge of the eye which circles the lens. When is contracts the lens gets fatter. When it relaxes the lens gets thinner

Answer 78

. Strong fibres which attach the lens to the ciliary miscle

Answer 79

. Contains light sensitive cells called rods and cones

Answer 80

. Consists of many neurones which carry impulses from the retina to the brain

Answer 81

. The region of the retina with the greatest number of cones

Answer 82

. A mucous membrane that covers the eye to prevent infection

Answer 83

. The eye is a sense organ containing receptors sensitive to light intensity and colour

Answer 84

. In dim light the RADIAL MUSCLES CONTRACT and circular muscles relax. This makes the iris narrower and the PUPIL DILATES

Answer 85

. In Bright light the CIRCULAR MUSCLES CONTRACT and radial muscles relax. This makes the iris wider and the PUPIL CONSTRICTS

Answer 86

. Iris reflex etc……

Answer 87

. …accommodation

Answer 88

. Almost parallel when they reach the cornea so the lens does not need to refract them much to focus light on the retina

Answer 89

. Light rays entering the eye are diverging so the lens needs to refract the light to ensure it focusses onto the retina

Answer 90

. When focusing on an object far away ciliary muscles RELAX

Answer 91

. When focusing on an object far away due to the ciliary muscles being relaxed the suspensory ligaments are pulled tight

Answer 92

. When focusing on an object far away the lens is pulled thin and has a less convex shape

Answer 93

. When focusing on an object Close up ciliary muscles contract

Answer 94

.When focusing on an object close up dues to the contracting ciliary muscles the suspensory ligaments are slack

Answer 95

. When focusing on an object close up Lens is not stretched out so becomes thicker with a more convex shape

Answer 96

. As the lens is less convex there is LESS REFRACTION of light

Answer 97

. As the lens is more convex there is more refraction of light

Answer 98

. The hair traps a layer of wait which, like a seals blubber provides INSULATION for conduction of heat

Answer 99

. Less sweat is released therefore less heat is lost via evaporation

Answer 100

. Vasoconstriction is when Arterioles supplying the capillaries near the surface of the skin get NARROWER -they CONSTRICT. LESS blood will flow through the capillaries near the surface of the skin, therefore LESS heat will be lost by RADIATION

Answer 101

. Vasodilation is when Arterioles supplying the capillaries near the surface of the skin get WIDER -they DILATE. MORE blood will flow through the capillaries near the surface of the skin, therefore MORE heat will be lost by RADIATION

Answer 102

. Hairs stand on end . Less sweat released . Vasoconstriction

Answer 103

. Hairs lie flat . More sweat is released . Vasodilation

Answer 104

. Hairs lie flat and therefore and insulating layer of air is not formed

Answer 105

. Sweat ISN’T cold - the sweat is secreted at NORMAL BODY TEMPERATURE. When the sweat EVAPORATES, heat energy is taken away from the skin as EVAPORATION OF WATER REQUIRES ENERGY

Answer 106

. Adrenal gland

Answer 107

. Pancreas

Answer 108

. Pituitary gland

Answer 109

. Pituitary gland

Answer 110

. Pituitary gland

Answer 111

. Increases heart rate and breathing rate for fight, fright or flight

Answer 112

. Causes liver and muscles to take up glucose and convert it to glycogen for storage

Answer 113

. Stimulates development of male secondary sexual characteristics

Answer 114

. Maintains uterus lining and controls the development of secondary female characteristics

Answer 115

. Stimulates uterus lining to develop and the development of secondary female characteristics

Answer 116

. Reduces the amount of water lost in urine

Answer 117

. Stimulates an egg to mature in the ovary

Answer 118

. Stimulates the release of an egg from the ovary (ovulation)

Answer 119

. A cell is the smallest possible unit of life

Answer 120

. Organelles are small structures which carry out jobs needed to keep the cell alive

Answer 121

. Chloroplasts . Vacuole . Cell wall

Answer 122

. Controls the activity of the cell ( by making proteins) . Controls the CHROMOSOMES

Answer 123

. Strands of DNA 🧬 which carry the genes (each gene codes for a protein)

Answer 124

. Boundary between the cytoplasm and the cell’s surroundings. Controls what substances enter and leave the cell (selectively permeable)

Answer 125

. Jelly-like liquid where CHEMICAL reactions occur

Answer 126

. Carries out some reactions of AEROBIC RESPIRATION, producing ATP

Answer 127

. An energy carrier molecule

Answer 128

. Synthesise (assemble) proteins from amino acids

Answer 129

. Absorb light energy and use it to carry out the chemical reactions of PHOTOSYNTHESIS, making biological molecules for plant cells

Answer 130

. Made of CELLULOSE (a carbohydrate) in plants. Helps to keep plant cells in a fixed shape (keeping the plant upright)

Answer 131

. Filled with a watery liquid called CELL SAP; stores dissolved sugars, mineral ions and other substances

Answer 132

. Diffusion is the random movement of particles from an area of high concentration to an area of lower concentration

Answer 133

. At higher temperatures, molecules have more kinetic energy and so move faster. Therefore diffusion occurs faster

Answer 134

. If there is a very large difference in concentration between two areas, molecules will diffuse from the higher to the lower concentration quickly. If the concentration gradient is small, diffusion will happen more slowly

Answer 135

. Diffusion takes longer if the molecules have to travel further (molecules don’t travel in a straight line). Therefore cells are small (smaller volume decreases distance)

Answer 136

. A larger surface area speeds up the rate of diffusion as there are more opportunities for the molecules to move , which is why surfaces such as alveoli in the lungs are so large

Answer 137

. This is more significant, as the two counteract each other: an efficient exchange surface has a surface area which is very large compared to the distance the molecules must travel

Answer 138

. SA :V is increased when structures are small

Answer 139

. Osmosis is 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

Answer 140

. *free water molecules* are what we describe as water molecules whose movement is not restricted by their environment

Answer 141

. A *partially permeable membrane* is a membrane that only allows certain particles through

Answer 142

. **water potential** is a measure of the concentration of free water molecules in a solution

Answer 143

. Pure water has a water potential of **zero**

Answer 144

. As solute is added, water potential falls as there will be a lower concentration of free water molecules.

Answer 145

. Concentrated solutions have a very LOW water potential.

Answer 146

. In osmosis, water moves from an area of **high water potential** to an area of **lower water potential**

Answer 147

. The solution outside the cell has the **same** *water potential* as in the cell

Answer 148

. The solution outside the cell has a **higher** *water potential* then inside the cell

Answer 149

. The solution outside the cell has a **lower** *water potential* then inside the cell

Answer 150

. No net movement

Answer 151

. Net movement of free water molecules into the cell

Answer 152

. Net movement of free water molecules out of the cell

Answer 153

. They become LYSED

Answer 154

. They are normal

Answer 155

. They become shrivelled

Answer 156

. They are Turgid (normal)

Answer 157

. They are flaccid

Answer 158

. They become plasmolyzed (plant wilts)

Answer 159

. Active transport is the movement of molecules from an area of low concentration to an area of high concentration using ATP

Answer 160

. Glucose is absorbed by active transport in the small intestine . Plants use in RHC to absorb mineral ions

Answer 161

. As it is used by organisms to transport substances AGAINST the concentration gradient ( using carrier proteins )

Answer 162

. Use agar cubes of different sizes - the cubes contain an *alkali* and an indicator (they are placed in acid) - as the acid diffuses into the cube it reacts with the alkali - turning the indicator colourless (Smallest cube becomes colourless fastest)

Answer 163

. Potato chips can be placed in sucrose or salt solutions of different concentrations - osmosis will occur until the water potential of the tissue and the solution are the same; (this causes a mass change) - LEAVE FOR 20 MINS

Answer 164

. If the solution has a higher water concentration , water will move into the potato chip and the mass will increase

Answer 165

. If the solution has a lower water concentration, water will move out of the potato chip and the mass will decrease

Answer 166

. Visking tubing ( only allows small soluble molecules to pass through ) - e.g. glucose and water . You could change the concentration of the sucrose solution - the height the liquid rises in a set time will increase if osmosis is faster

Answer 167

. Visking tubing ( only allows small soluble molecules to pass through ) - e.g. glucose and water . You could change the temperature of the water - the height the liquid rises in a set time will increase if osmosis is faster

Answer 168

. Use thin sections of onion cells - TURGID- soaked in pure water - PLASMOLYSED- soaked in a concentrated salt solution

Answer 169

. Plants use the simple molecules CARBON DIOXIDE and WATER to make GLUCOSE and OXYGEN (Using light energy)

Answer 170

. It is absorbed by the chlorophyll in their chloroplasts

Answer 171

. Photosynthesis converts **light energy** into stores **chemical energy** which can be used by the organism for respiration

Answer 172

1. The availability of the substrates for the reaction by - **carbon dioxide and water** 2.The energy available to allow the reaction to occur - **light intensity** 3. The kinetic energy available to move substrate and enzyme molecules - increasing the **temperature**

Answer 173

. By adding **more carbon dioxide** the reaction can happen faster, as there are more molecules to collide with the enzymes. However, we reach a point when adding more carbon dioxide has no effect - There is a lack of energy.

Answer 174

. By adding a bright light we increase the rate of photosynthesis, as there is **more energy** for the reaction to occur. This doesn’t last forever as at high light Intensity is a different factor is limiting (and so the graph levels off).

Answer 175

Increasing temperature speeds up the reaction. This is because the enzymes and substrates have **more kinetic energy** and collide more often. However, at high temperatures the rate of photosynthesis decreases and the reaction stops. This is because the **enzymes** carrying out the stages of photosynthesis have been **denatured**.

Answer 176

. Beaker . Water plant . Funnel . Boiling tube . Splint . Bunsen burner . Heatproof mat

Answer 177

. Take a bundle of shoots of the 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.

Answer 178

. Relight a glowing splint

Answer 179

. A Length of pond weed (ELODEA) is put in a beaker of water and the number of bubbles released from the stalk in one minute is counted. The **distance of a bench lamp** can we move to vary the light intensity,or differing **masses of sodium bicarbonate** to vary the carbon dioxide concentration.

Answer 180

. They are biological molecules which are required by the body

Answer 181

. Bread . Rice . Potatoes

Answer 182

. Meat . Eggs . Fish . Quinoa

Answer 183

. Butter . Avocados . Cream

Answer 184

. Fuel for respiration

Answer 185

. Growth and repair of cells and tissues . Fuel for respiration

Answer 186

. Store of energy . Thermal and electrical insulation . Fuel for respiration

Answer 187

. Red meat . Spinach . Liver

Answer 188

. Milk and dairy products . Fish . Fresh veg

Answer 189

. Forms part of the haemoglobin which binds to oxygen

Answer 190

. Needed to form bones and teeth

Answer 191

. Fish liver oil . Butter . Carrots

Answer 192

. Fresh fruit and vegetables

Answer 193

. Dairy products . Oily fish

Answer 194

. Making a chemical in the retina and also protects the surface of the Eye

Answer 195

. Needed for cells and tissues to stick together

Answer 196

. Needed to absorb calcium and phosphate ions from food

Answer 197

. Night blindness . Damaged cornea

Answer 198

. Rickets, caused by weak bones

Answer 199

. it is an essential solvent (*things can be dissolved in it*) It is used to transport the components of blood and is crucial for temperature regulation. Eg: sweating

Answer 200

. Helps the movement of food through the intestines, preventing, constipation and bowel cancer

Answer 201

. Fruit and vegetables, along with grains are all good sources of fibre as they all contain cellulose.

Answer 202

Ingestion➡️digestion➡️absorption➡️ ➡️Egestion

Answer 203

. The expulsion of faeces through the anus. In other words, it is the removal of undigested food from the body.

Answer 204

. The removal of waste substances produced by chemical reactions in the body for example, carbon dioxide (removed by lungs) and urea.

Answer 205

. Carbohydrates

Answer 206

. Proteins

Answer 207

. Smaller carbohydrate molecules, E.g. glucose

Answer 208

. Amino acids

Answer 209

. Glycerol +3 fatty acids

Answer 210

. Mouth And . Duodenum

Answer 211

. Duodenum

Answer 212

. Duodenum

Answer 213

. Duodenum

Answer 214

. Duodenum

Answer 215

. Salivary glands And . Pancreas

Answer 216

. Gastric glands in stomach wall

Answer 217

. Pancreas

Answer 218

. Lining of duodenum

Answer 219

. Lining of duodenum

Answer 220

. Starch to maltose

Answer 221

. Proteins to peptides

Answer 222

. Lipids to fatty acids + glycerol

Answer 223

. Proteins to peptides

Answer 224

. Maltose to glucose

Answer 225

. Peptides to amino acids

Answer 226

. In the thorax

Answer 227

When we breathe in air passes down the trachea, this tube is surrounded by C-shaped rings of cartilage. These keep the trachea open but make swallowing easier.

Answer 228

The bronchi are two tubes that lead to the lungs. These Bronchi are also surrounded by cartilage rings.

Answer 229

Bronchioles are smaller tubes which carry a deep into the thorax

Answer 230

At the end of each bronchiole, there are microscopic air sacs, the alveoli these are the site of gas exchange

Answer 231

The lungs are surrounded by the plural membrane. This forms a layer between the lungs in the thorax walls . They form an airtight seal and prevent the lungs from sticking to the thorax wall as they inflate and deflate.

Answer 232

The ribs help protect the organs in the thorax

Answer 233

Intercostal muscles between the ribs, help to connect the bones and are important in moving air into and out of the lungs

Answer 234

It’s a domed sheet of muscle and fibrous tissue. It’s also important in moving air into and out of the lungs.

Answer 235

Ventilation is the process of moving air into and out of the lungs

Answer 236

.The diaphragm contracts, moving down and flattening . Intercostal muscles contract, moving rib cage up and out. . This causes the volume of the thorax to increase and air pressure in the thorax to fall . Air pressure is now less than atmospheric pressure, meaning moves into the lungs.

Answer 237

. Diaphragm relaxes, moving up and doming. . Intercostal muscles relax, moving rib cage down and in . This causes the volume of the thorax to decrease and air pressure in the thorax to rise. . Air pressure is now more than atmospheric pressure, meaning air moves out of the lungs.

Answer 238

. There are an enormous number of alveoli in the lungs. This large surface are = more diffusion . Each alveolus is surrounded by network of capillaries. This maintains a high concentration gradient so = more diffusion . The walls of the alveoli are only one cell thick . There is a small diffusion distance = more diffusion

Answer 239

. They constantly carry deoxygenated blood to the Alveolus and move oxygenated blood away.

Answer 240

Tobacco smoke contains carbon monoxide. This irreversibly binds to haemoglobin reducing the amount of oxygen transported to the blood. . Chemicals in tobacco, destroy cilia. At the same time mucus production will increase, in response to the smoke, The mucus cannot be moved out of the airways quickly (no cilia) so builds up causing smokers cough also increasing the risk of infection (bronchitis) . Smoke also reaches the alveoli damaging them, decreasing the surface area for gas exchange, so less oxygen defuses into the blood (emphysema)

Answer 241

. smoking increases blood pressure and increases the risk of fatty deposits forming.

Answer 242

. The fatty deposits narrow the lumen of the artery. This means the narrow coronary arteries have a reduced blood flow to the heart muscle cells. This means that the heart muscle cells receive less oxygen for aerobic respiration and anaerobic respiration increases. Lactic acid builds up, poisoning the heart muscle cells and causing a heart attack.

Answer 243

Count the number of breaths someone takes in one minute at rest, then ask you subject to exercise e.g. jogging on the spot for five minutes count. The number of breaths they take the first minute after exercise. . You need to carry out the experiment and lots of people . control variables: age, gender, fitness, type of exercise and length of exercise

Answer 244

. Using a t-tube arrangement, going from a mouthpiece into two conical flasks, bubble inhaled and exhaled air through an indicator. . using lime water, milky white in exhaled air and remains colourless in inhaled air test tube

Answer 245

. Phloem transports sucrose and amino acids from the leaves to the growing points or storage areas.

Answer 246

. The tips of the shoots and flowers

Answer 247

. Roots or bulbs

Answer 248

. In the leaves

Answer 249

. The phloem consist of living cells . Tubes are formed by cells that are arranged to end, but have cell walls made of Cellulose . moving the sucrose and amino acids around the 🌱 (up and down the stem) requires energy. This is called translocation.

Answer 250

. Transports water and mineral ions from the roots to the leaves.

Answer 251

. The xylem is made up of thick walled dead cells which contain no cytoplasm. They are completely hollow and arranged End to end . Cell walls contain lignin, which is waterproof. . The end walls have broken down, so they form a continuous transport system through the plant.

Answer 252

. Nitrate ions are needed to make amino acids and proteins

Answer 253

. Magnesium ions are needed to make chlorophyll.

Answer 254

. RHCs are thin walled and have hair like extensions that increase the surface area of the root epidermis .The water has some solutes dissolved in it, but their concentration is much lower than the concentrations of the solute inside the root hair cells. The soil water has a higher concentration of water molecules and water will enter the cell by **osmosis**

Answer 255

. the function of a root hair is to absorb water and mineral ions from the soil

Answer 256

. Root hair cells (*are the main site of water absorption by the root*)

Answer 257

. Transpiration is the evaporation of water from the surface of a plant

Answer 258

. Temperature . Humidity . Windspeed . Light intensity

Answer 259

. On a hot day, water will evaporate quickly from the leaves of a plant as the water molecules have more kinetic energy . Transpiration will increase as temperature increases.

Answer 260

. humid air contains a lot of water vapour. There is a small a concentration gradient so transpiration slows down. . In dry air the diffusion of water vapour from a leaf to the atmosphere will be fast. . Transpiration, therefore increases if humidity decreases

Answer 261

. In still air the area around a transpiring leaf will become saturated with water vapour, so no more can escape from the leaf, meaning transpiration is slower. . In moving air, water vapour is blown away from the leaf as fast as it diffuses out. Speeding up transpiration. . Transpiration increases as wind speed increases.

Answer 262

. Light itself does not affect evaporation, but in daylight, the stomata of leaves are open to supply carbon dioxide for photosynthesis. Allowing more 💦 to diffuse out of the leaves and into the atmosphere.

Answer 263

1. The potometer must be set up underwater 2. Cut the stem of a shoot 3. Put the shoots them into a bong, grease the joint with plenty of petroleum jelly 4. Put the bung into the potometer 5. And make sure the tap is closed and it’s full of water, No bubbles. Then lift the potometer out of the water. 6. Leave the end of the capillary tube without water until an air bubble forms, then put the end into a beaker of water 7. You can measure the transpiration rate as distance the bubble travels in five minutes (you should take a number of readings and calculate a mean rate).

Answer 264

This prevents any air bubbles from entering the system and blocking the xylem

Answer 265

. Using a hairdryer on cold

Answer 266

. Using a clear plastic bag

Answer 267

. Darkness

Answer 268

A= aorta B=pulmonary artery C= pulmonary vein D= left atrium E= bicuspid valve F= left ventricle G= semi-lunar valve H= semi-lunar valve I= right ventricle J= tricuspid valve K= inferior vena cava L= right atrium M= superior vena cava

Answer 269

. The right side of the heart pumps deoxygenated blood to the lungs.

Answer 270

. The left side of the heart pumps oxygenated blood to the body.

Answer 271

. The left ventricle wall is much thicker than the right ventricle, allowing it to pump blood at high-pressures so that the blood can travel around the whole body.

Answer 272

. The two sides of the heart contract and relax at the same time, the atria contract emptying blood into the ventricles. The ventricles, then contract pushing blood into the arteries valves close to ensure blood flows in the correct direction.

Answer 273

. The medulla

Answer 274

. If we exercise, our muscles need more glucose and oxygen for aerobic respiration, the heart rate increases so that more blood travels to the muscles.

Answer 275

. When exercise starts, muscles produce more carbon dioxide in aerobic respiration. .Sensors in the aorta detect this increase .They send nerve impulses to the medulla . An accelerator nerve increases heart rate . More blood supply to the muscles to meet increased aerobic respiration

Answer 276

. Adrenaline

Answer 277

. Diet . Smoking . High blood pressure. . Obesity . Lack of exercise.

Answer 278

. Eating lots of saturated fat increases blood cholesterol and increases the risk of fatty deposits.

Answer 279

. Increases the blood pressure and increases the risk of fatty deposits forming

Answer 280

. It damages, the artery lining and increases the risk of fatty deposits forming. High salt levels in your diet increase the risk of high blood pressure.

Answer 281

. Being obese will increase blood pressure and may be linked to poor diet.

Answer 282

. Causes high blood pressure.

Answer 283

. Thick outer wall. . Thick layer of elastic tissue. . Thick layer of muscular tissue. . Small lumen

Answer 284

. Can transport blood at high-pressure without bursting.

Answer 285

. Elastic tissue allows artery to stretch and recoil to keep blood flowing at high-pressure

Answer 286

. The thick layer of muscular tissue helps to control the flow of blood by widening and narrowing

Answer 287

. Fairly thin outer wall . Then layer of muscle and elastic tissue . Semi lunar valves

Answer 288

. Blood is flowing at a lower pressure, so thick wall not needed.

Answer 289

. Wall can contract to keep blood flowing.

Answer 290

. Prevents blood flowing backwards.

Answer 291

. Wall is one cell thick.

Answer 292

. Short distance for diffusion of substances from blood into tissues.

Answer 293

. Carbon dioxide . Oxygen (*form the stomata of a leaf*)

Answer 294

. Protein in dead plants and animals is broken down. . Ammonia is released into the soil.

Answer 295

Ammonia is converted into nitrates and nitrites are converted into nitrates

Answer 296

. Nitrates are converted into nitrogen gas (*denitrification reduces the amount of nitrate in the soil and therefore makes the soil less fertile*)

Answer 297

. Nitrogen gas is converted to ammonia in bacteria which is used to make proteins, when the bacteria die the proteins decompose, releasing ammonia back into the soil.

Answer 298

. Decomposing bacteria.

Answer 299

. nitrifying bacteria.

Answer 300

. Denitrifying bacteria.

Answer 301

Nitrogen fixing bacteria, (*found in soil, and in root nodules of plants*)

Answer 302

. Cells are the smallest functional unit of life and contain a number of **organelles**

Answer 303

A structure that carries out a specific process the cell needs to survive

Answer 304

Tissues are groups of similar cells, which work together to carry out the same function

Answer 305

Muscle tissue

Answer 306

Organs are made up of several different tissues working together to carry out a more complex function.

Answer 307

Organ systems are made up of several different organs working together to carry out a complex function essential to life

Answer 308

These are not specialised to a particular job, but are able to divide many times by **mitosis** to make new cells

Answer 309

. “**stem cells**”

Answer 310

A cell which has the structures and proteins needed to carry out a specific job in the organism

Answer 311

They **differentiate** (develop new features.

Answer 312

**differentiation** is controlled by genes

Answer 313

During differentiation **genes are ‘switched off’** (silenced) so that they cannot be transcribed. This ensures the only proteins produced in the specialised cell are the ones needed to carry out its particular job

Answer 314

In humans there are **two types of stem cells**: - **embryonic** - **adult**

Answer 315

**Embryonic stem cells** are found in the early form of the embryo. They can differentiate into **any** type of cell

Answer 316

. Adult stem cells are present in some tissues in organisms. There are several different types. They divide by mitosis and each type of stem cell can differentiate into a **few different types of specialised cell**

Answer 317

Bone marrow stem cells ( can only form blood cells and bone cells )

Answer 318

. Stem cells can potentially be used to: -**treat many different diseases** - repair damaged tissues - and even grow new organs for transplant

Answer 319

Currently we can transplant adult stem cells

Answer 320

If someone has a damaged immune system ( perhaps due to cancer/ Leukaemia) they may receive a bone marrow transplant.

Answer 321

. They are easy to collect for treatment

Answer 322

. They can only become a limited number of cell types

Answer 323

Scientists collect embryonic stem cells and culture them- grow large numbers in a lab. They are investigating how to instruct these cells to form different types of tissue for medical treatment

Answer 324

Many people object morally, as the cells come from extra embryos which were not used in IVF treatments ( parents choose to donate these embryos to research, however, they could potentially have developed into humans )

Answer 325

Where eggs are fertilised in a lab, and some embryos are implanted into the uterus

Answer 326

. Fuel for **respiration**

Answer 327

A:upper epidermis B:xylem C:phloem D:stomata E:cuticle F:palisade (mesophyll) G:spongy mesophyll H:lower epidermis I: guard cells

Answer 328

The leaf has a **large surface area** and is **thin**, to maximise absorption of sunlight by the photosynthetic cells.

Answer 329

It increases the number of stomata so that carbon dioxide can diffuse quicker (they provide a short diffusion distance for carbon dioxide)

Answer 330

The upper epidermis is transparent, allowing light to penetrate the mesophyll

Answer 331

The palisade cells are long, thin and tightly packed. They contain large numbers of **chloroplasts**. This maximises the absorption in sunlight energy.

Answer 332

The **palisade mesophyll**

Answer 333

. Stomata allow gases to diffuse into the air spaces of the leaf

Answer 334

The xylem transports water (absorbed in the roots) into the leaves. This then provides a short distance for water to diffuse into the photosynthesising cells

Answer 335

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

Answer 336

. Mineral ions

Answer 337

. Magnesium ions

Answer 338

. Nitrate ions

Answer 339

. On average a teenage boy needs more energy than a pregnant woman ( for growth )

Answer 340

. Kilojoules (kj)

Answer 341

. Around 70% of energy we use everyday is just to keep our body running ( to keep our heart beating, transport nutrients-active transport- + repair our cells) . The remaining 30% can be used for extra work + activities eg: walking or running

Answer 342

Humans and all mammals

Answer 343

Food is **ingested, digested, absorbed** and **egested** from this canal for the purpose that the food can be **assimilated**

Answer 344

. Duodenum . + ileum

Answer 345

. Colon . + anus

Answer 346

. Taking food through the mouth and swallowing

Answer 347

. Breaking down large insoluble molecules in food into smaller pieces (physical digestion) and smaller, soluble molecules (chemical digestion)

Answer 348

Movement of small soluble molecules out of the gut and into the blood by diffusion and active transport

Answer 349

Passing out undigested food through the anus

Answer 350

. Building larger biological molecules from the small soluble molecules, in all cells

Answer 351

. This is where **Ingestion** takes place . Digestion also begins here

Answer 352

. Digestion, the breakdown of large insoluble molecules into small soluble molecules

Answer 353

Food here is broken up into smaller pieces in the mouth by **chewing**

Answer 354

It increases the surface area for enzymes and also prevents discomfort when swallowing

Answer 355

**Saliva** is released into the mouth by the salivary glands. It makes food easier to swallow, and also contains the enzyme **amylase**.

Answer 356

Amylase breaks down the starch to maltose STARCH➡️(*amylase*)➡️MALTOSE

Answer 357

Amylase works best at a neutral pH, so is **denatured** when it reaches the stomach and stops working

Answer 358

Before swallowing the food is shaped into a ball by the younger and moved towards the back of the mouth ( the ball is called a **bolus**)

Answer 359

There is a flap called the **epiglottis** which blocks the food from entering the trachea

Answer 360

The oesophagus is a long tube that connects the mouth to the stomach

Answer 361

. Food is pushed down by **peristalsis**. (*Food is also moved by peristalsis along the small and large intestines*)

Answer 362

Two sets of muscles push food down the oesophagus. The **circular muscles contract behind** the bolus, pushing it along. When the **longitudinal muscles contract** they make the oesophagus wider

Answer 363

The gastric glands

Answer 364

. It begins the process of digesting proteins into peptides (shorter chains of amino acids) PROTEIN➡️(*pepsin*)➡️PEPTIDE

Answer 365

. The stomach walls contract and causes mixing of the contents of the stomach

Answer 366

Pepsin’s optimum conditions are an **acidic pH**.

Answer 367

Due to the release of **hydrochloric acid** by the **gastric glands**

Answer 368

. HCl has a **very low pH** and would burn through the stomach if it was not covered by a **mucus lining**

Answer 369

. To provide optimum pH for pepsin . To kill many bacteria and fungi which may be present in the food we eat

Answer 370

. Both digestion and absorption happen in the small intestine (Digestion happens in the first section, the **duodenum**)

Answer 371

The duodenum is the final site of chemical digestion. The **Pancreas** makes several enzymes and secretes them into the duodenum

Answer 372

**Trypsin**: PROTEIN➡️(*trypsin*)➡️PEPTIDE **amylase**: STARCH➡️(*amylase*)➡️MALTOSE **lipase**: LIPID(fat)➡️(*lipase*)➡️GLYCEROL+3 . fatty acids

Answer 373

**maltase**: MALTOSE➡️(*maltase*)➡️GLUCOSE **peptidase**: PEPTIDE➡️(*peptidase*)➡️AMINO. .ACIDS

Answer 374

. By the liver

Answer 375

. In the hall bladder

Answer 376

. Through the bile duct

Answer 377

1. **neutralises** the stomach acid. (*enzymes in the duodenum work best at pH 7-8*) 2. **emulsifies lipids**, breaks down large droplets into smaller droplets (*increasing the surface area for lipase to digest the fats*)

Answer 378

The **ileum** has many folds and is covered in many finger like projections called **villi**

Answer 379

. They absorb small soluble molecules. (*some are absorbed by* **diffusion** *however some are also absorbed by* **active transport**)

Answer 380

. Absorption which moves particles against the concentration gradient using ATP

Answer 381

. Large surface area . Short diffusion distance . High concentration gradient

Answer 382

. Folding of ileum . **villi** and **microvilli** (*folds on the surface of cells lining the villi*) all increase surface area

Answer 383

. The villi walls are **one cell thick**

Answer 384

. The high concentration gradient is provided by the **capillary network** and **lacteals** which remove absorbed molecules

Answer 385

. Colon And . Rectum

Answer 386

The colon is the site for all reabsorption of water

Answer 387

Faeces are stored in the rectum and then egested from the anus

Answer 388

. Egestion is the expulsion of faeces through the anus. (*the removal of undigested food from the body*)

Answer 389

Excretion is the removal of waste substances produced by chemical reactions in the body

Answer 390

. Carbon dioxide (excreted by the lungs) . Urea (removed by the kidneys and sweat)

Answer 391

Assimilation takes place In all cells using the food molecules absorbed to build more complex molecules such as protein

Answer 392

All cells need a **source of energy**, this energy is provided by **ATP**

Answer 393

**Cell respiration** is the process of ***breaking down food molecules to release ATP***. (*It is a series of chemical reactions*)

Answer 394

. Cell division . Building large molecules (such as proteins) . Contraction of muscle cells (movement) . Transporting molecules (eg active transport) . Maintaining body temperature

Answer 395

**Aerobic respiration** uses oxygen to breakdown, glucose and release energy

Answer 396

Some energy is released as heat most is trapped in a usable form of ATP

Answer 397

Glucose+ oxygen➡️carbon dioxide . +. ➕water

Answer 398

Aerobic respiration releases a lot of ATP because it completely oxidises the glucose

Answer 399

When cells can respire without using oxygen, this is called **anaerobic respiration**

Answer 400

In anaerobic respiration, **glucose is not completely broken down**, so less ATP and therefore less energy is released

Answer 401

Anaerobic respiration also produces toxic waste products, which must either be excreted or broken down such as lactic acid

Answer 402

The advantage of anaerobic respiration is that it allows cells to obtain a small amount of usable energy when the oxygen supply is limited

Answer 403

Glucose➡️ ethanol + carbon dioxide

Answer 404

Anaerobic respiration is very useful in **food production**. We use **yeast** (*a single celled fungus*) in bread and alcohol production.

Answer 405

In both processes, we supply **glucose** and keep the yeast in **low oxygen conditions** so that the cells respire **anaerobically**. The carbon dioxide produced forms bubbles in bread dough, causing it to rise, and the ethanol provides alcohol content in beer and wine .

Answer 406

Glucose ➡️ lactic acid

Answer 407

This process occurs in muscle cells when there is a shortage of oxygen e.g. during intensive exercise

Answer 408

If muscles are worked very hard, they need **large quantities of energy**, more than can be provided by aerobic respiration. The **glycogen stored in the muscle cells** is **broken down into glucose**. This is respired **anaerobically**, providing an additional energy supply.

Answer 409

Lactic acid builds up, causing cramps and diffuses from muscles into the blood

Answer 410

The **glycogen stored in the muscle cells** is **broken down into glucose**. This is respired **anaerobically**, providing an additional energy supply.

Answer 411

In high concentrations, lactic acid is toxic

Answer 412

It is transported to the liver where it is oxidised

Answer 413

(*Oxidation of lactic acid in the liver uses oxygen*), we keep breathing heavily after exercise to supply the extra oxygen needed to dispose of the lactic acid in our bodies

Answer 414

Oxygen debt is the volume of oxygen needed to oxidise the lactic acid, in the liver

Answer 415

The central nervous system is linked to sense organs **by nerves**

Answer 416

. Blood is a complex tissue

Answer 417

Blood is a complex tissue, consisting of .a liquid component **(plasma)** .cell fragments, **platelets** .and two types of cells, **red and white blood cells**

Answer 418

Straw colored liquid

Answer 419

Small red cells

Answer 420

Cell fragments

Answer 421

Larger cells with a multi-lobed nucleus

Answer 422

Cells with a very large nucleus

Answer 423

Plasma transports blood cells and many other substances, including dissolved nutrients

Answer 424

**dissolved nutrients**, .such as **glucose** and **amino acids** .dissolved waste products, including **urea** and **carbon dioxide**, **hormones**, **proteins**, and **heat energy**

Answer 425

To transport oxygen bound to haemoglobin

Answer 426

Platelets release chemicals when the blood is exposed to air

Answer 427

The chemicals cause soluble fibrinogen to be converted into insoluble fibrin

Answer 428

(*Chemicals produced by platelets convert soluble fibrinogen into insoluble fibrin*) **Fibrin forms a mesh which traps platelets in red blood cells. This is a clot.**

Answer 429

Phagocytes **engulf and digest pathogens**

Answer 430

A pathogen is a microorganism, which causes disease

Answer 431

Lymphocytes *^make and release antibodies**, which bind to and destroy pathogens

Answer 432

.Red blood cells contain **haemoglobin** . They have **no nucleus** . They are **biconcave**

Answer 433

Haemoglobin is a protein which combines with oxygen to form **Oxyhemoglobin this transports oxygen to respiring cells**

Answer 434

Red blood cells have no nucleus, meaning that **more haemoglobin** can be packed into each cell and so **more oxygen** to be transported

Answer 435

Red blood cells are **biconcave** (discs with a dip in the middle. This **increases the surface area: volume ratio** and **decreases the distance to the centre of the cell**. This **increases the rate of diffusion**

Answer 436

A disease is a condition that prevents the body or part of it working properly

Answer 437

Most diseases are caused by microorganisms, **pathogens** ( e.g **viruses and bacteria** )

Answer 438

By entering the body and feeding and reproducing in it, they damage the body or poison it by **excreting toxic waste substances called toxins**

Answer 439

The skin and membranes of the body

Answer 440

If the barriers become damaged, then **white blood cells** take over the defence of the body

Answer 441

Phagocytes and lymphocytes

Answer 442

1. Phagocyte recognises pathogen. 2. phagocyte engulfs, a pathogen in a process known as **phagocytosis** 3. The **lysozymes** containing the enzymes move towards the pathogen. 4. enzymes break down the pathogen. 5. useful materials are absorbed 6. waste products are removed from the phagocyte

Answer 443

Phagocytes s are a type of white blood cell **engulfs and digest** pathogens that they encounter. This is called phagocytosis.

Answer 444

a special Y-shaped protein

Answer 445

Antibodies are what lymphocytes produce

Answer 446

Antibodies attach to proteins on the surface of pathogen is called **antigens**

Answer 447

Each pathogen has a different shaped antigen, so the lymphocytes need to make a specific complementary antibody

Answer 448

Lymphocyte allow organisms to build up an **immunity** toward certain diseases

Answer 449

1. **lymphocytes detect** pathogen’s **antigens** 2. Lymphocyte identifies the correct type of **antibody** to make which is complimentary to the pathogen is antigen. 3. Lymphocyte releases **large numbers** of correct Antibody 4. Pathogens either clump together, resulting in death or the antibodies trigger phagocytes (*some pathogens even burst*) 5. Lymphocytes produce cells that produce lots of the antibody very quickly if they detect the same pathogen again. these are called **memory cells**

Answer 450

. Some antibodies are specialised to combat toxins, chemicals released by pathogen, which cause cell damage these are called **anti-toxins**

Answer 451

chemicals released by pathogen, which cause cell damage.

Answer 452

Most plants do not respond quickly **they respond slowly by changing their rate of growth** (*Some plants like the -Venus fly- trap can respond quickly*)

Answer 453

Plants can respond to a stimulus such as **light** (*plants, place near a window will grow towards the light*)

Answer 454

The growth of a plant towards a directional stimulus is called a **tropism**

Answer 455

**Phototropisms** are growth responses to **light** from one direction

Answer 456

Growth **towards** the light from a single direction is called **positive phototropism**

Answer 457

Auxin, the hormone that controls controls **phototropic growth** is found in the top of the stem

Answer 458

The tip of the shoot produces the Auxin, which diffusers down the shoot to cause elongation (lengthening) of cells

Answer 459

When light intensity is higher on one side of the stem, **auxins buildup on the shaded side**. This causes the **cells** on the shaded side to **elongate more** as a result the **shoot bends towards the light**

Answer 460

A- tips are cut off, therefore no growth B- tips covered. Therefore the stem grows directly upwards (no light reached the tip) C- stem grows towards the light, this is called positive phototropism

Answer 461

**Geotropism** is the growth towards or away from **gravity**

Answer 462

Roots are **positively geotropic**