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last min Flashcards

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Biology 101 flashcards
1
Q

How do multicellular organisms exchanged substances with their environment

A

more difficult to exchange substances over entire body so they have transport systems to move substances from exchange surface to rest of body due to smaller surface area to volume ratio.

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2
Q

How are alveoli adapted for gas exchange

A
  • moist lining for dissolving gases
  • good blood supply to maintain the concentration gradients of O2 and CO2
  • very thin walls
  • very large surface area
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3
Q

What is the function white blood cells

name the 2 types

A

to defend against infection

  • phagocytes are white blood cells which can change shape to engulf unwelcome microorganisms through phagocytosis
  • Lymphocytes -produce antibodies against microoragnisms. Some may produce antitoxins to neutralise any toxins produced by microoragnisms
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4
Q

How are Capillaries adapted for their function

A
  • branch off arteries
  • narrow to squeeze between gaps between cells
  • one cell thick cell walls so substances can diffuse
  • supply food and oxygen + take away CO2
  • exchange substances with cells
  • large lumen
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5
Q

What kind of circulatory do mammals have

A

Double circulatory, means heart pumps blood in two circuits
-deoxygenated blood goes to lungs to get oxygen
oxiginated blood goes to heart.
-second circuit takes ooxygenated blood from heart to the body for cells then returns to heart

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6
Q

name an animal with a single circulatory system and how it works

A

Fish- deoxygenated blood from fish body goes to heart which pumps around again via gills which pick up
oxygen.
-heart only has 2 chambers

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7
Q

How is deoxygenated blood carried around heart

A

through the vena cava

  • to right atrium
  • through tricuspid valve, through right ventricle
  • through semi lunar valve
  • to lungs through pulmonary artery
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8
Q

How is oxygenated blood carried around heart

A
  • through the pulmonary vein to left atrium
  • through bicuspid valve,
  • to left ventricle
  • through semi-lunar valve
  • through aorta to the body
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9
Q

What is the energy released by cellular respiration used for

A
  • metabollic processes- like breakdown of proteins from amino acid
  • contracting muscles-
  • maintaining a steady body temperature
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10
Q

How does anaerobic occur

A

when there isnt oxygen available so glucose is only partly broken down to make lactic acid which can build up in muscles and lead to cramp

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11
Q

What is the formula for anaerobic respiration in plants

A

glucose&raquo_space;»» ethanol + carbon dioxide

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12
Q

Why are photosynthetic organisms producers of biomass

A

Because they use energy from the sun to produce glucose

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13
Q

What substances are produced from glucose and their roles in the plant

A

energy which is used for respiration

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14
Q

How are leaves and their cells adapted for photosynthesis

A

Palisade layer has lots of chloroplasts so theyre near the top of the leaf
broad with large surface area exposed to light for photosynthesis

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15
Q

What are the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis

A

Light intensity- when high intensity, rate of photosynthesis speeds
Carbon dioxide- two little slows it down as its a raw material needed
Temperature- If too hot enzyme denatures too low enzymes dont work

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16
Q

what is the concentration gradient

A

The direction osmosis and diffusion take from a high to low concentration.
active transport goes against the concentration gradient

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17
Q

How is a Xylem tube adapted for its function

A

dead cells joined together end to end with no end walls to take water from roots to stem and leaves.
strengthened with lignin
carry mineral ions too up the transpiration stream

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18
Q

Why is the phloem tube adapted to its function? What is translocation

A

Elongated living cells with small pores on end walls so food substances can diffuse through.
they transport food substances made in leaves to other parts of the plant through process of translocation

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19
Q

What is transpiration

A

caused by evaporation and diffusion
occurs usually in leaves
its the loss of water from a plant

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20
Q

What effects the rate of transpiration

A

Light intensity- brighter light the greater the rate as stomata close when its dark.
Temperature- warmer means faster transpiration as particles have more energy to evaporate and transpire
Air flow- better the air flow the more transpiration as water vapour is swept away maintaining low water concentration on surface of leaf so diffusion occurs faster

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21
Q

How can you measure the rate of transpiration

A

using a potometer and record position of air bubble. start time and measure distance moved. calculate the speed of bubble

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22
Q

What are the functions of these layers of leaves

A

Waxy cuticle- reduces water loss
upper epidermis- light is allowed through as this layer in transparent
Palisade layer- lots of chloroplasts near top so lots of light
Spongy mesophyll tissue- contains air space which increases the rate of diffusion
lower epidermis- lots of stomata which lets CO2 diffuse directly into the leaf

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23
Q

How do auxins cause phototropism

A

auxins in tips of shoots makes all side elongate so a taller shoot gets more light

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24
Q

How can plant growers use auxins

A

selective weed killers- only effect broad leaf plants- disrupts plant growth
growing cuttings from rooting powder- conatins auxins which produce shoots very quickly and can create clones

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25
Q

How can plant growers use Gibberellins

A

-controlling seed germination- make plants flower earlier or under conditions they wouldnt normally flower it stimualtes SEED GERMINATION
(can also reduce flower formation to improve fruit quality)
-proudcing seedless fruit- applied to unpollonated flowers to so fruit grows but seeds dont
-Controlling seed germination - getting seeds to germinate at time of year they would normally

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26
Q

How can we artificially ripen fruit with hormones

A

Controlling ripening of fruit- ethene is added to fruit on the way to the supermarket so when they get there the fruit will be perfect on the shelves

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27
Q

Advantage of using plant hormones in fruit farming?

A
  • Get fruit at times of year where conditions wouldnt usually be right,
  • produce seedless fruit
  • produce clones of one plant
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28
Q

Disadvantages of Plant hormones in fruit farming

A
  • Harmful to environment- fertilisers and chemicals can leak into waters
  • fruit may be poor quality
  • traditional farmers out of business
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29
Q

Where are hormones produced

A

In endocrine glands which release into blood stream

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30
Q

What is the general role of hormones in the body

A

They control things in organs and cells that need constant adjustment

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31
Q

How are hormones transported around the body

A

They are chemical messengers released directly into the blood

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32
Q

What is produced by the pituitary gland

A

Produces many hormones that regulate body conditions

Master gland as hormones created act on other glands directing them to release hormones which create change

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33
Q

What is produced by the Thyroid gland

A

Produces thyroxine- regulate metabolism heart rate and temperature

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34
Q

What is produced by the Ovaries

A

Oestrogen- controls mentrual cycle

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35
Q

What is produced by the Adrenal Gland

A

Adrenaline- prepare body for fight or flight

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36
Q

What is produced by the Testes

A

Testosterone- controls puberty and sperm production in males

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37
Q

What is produced by the Pancreas

A

Insulin which regulates blood glucose concentration

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38
Q

How does adrenaline prepare body for fight or flight

A

Activates processed that increase supply of oxygen and glucose to cells by binding to receptors in heart and liver to increase blood pressure glucose concentration and respiration

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39
Q

What is a metabolic rate

A

The speed chemical reactions occur in the body

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40
Q

What is the effect of thyroxine on metabollic rate? and a negative feedback system

A

When thyroxine level is too LOW, hypothalamus releases TRH which stmulate the pitauitary gland making TSH which stimulates the release of thyroxine to get level in blood back to normal

If too HIGH the release or TRH from the hypothalamus is inhibited, which reduces production of TSH so blood thyroxine level falls

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41
Q

What happens in the menstrual cycle

A

Stage 1- menstruation - Lining of uterus breaks down and is released

Stage 2- uterus lining is repaired (4-14) becomes thick layer of blood vessels

Stage 3- day 14 is ovulation egg released from ovary

Stage 4- lining (endometrium) is maintained until day 28 if no fertilised egg landed on uterus by then lining breaks down

42
Q

What does Oestrogen do in the menstrual cycle

A

Causes uterus lining to thicken and grow

high level stimulates LH surge

43
Q

What does progesterone do

A

released by corpus luteum after ovulation it maintains lining of uterus
when low level lining breaks down

44
Q

How can hormones be used as a contraception

A

Oestrogen can prevent release of egg if levels are very high which is why pill must be taken everyday to inhibit production of FSH so egg development stops. `

Progesterone reduces fertility by producing thick cervical mucus which which stops sperm getting

45
Q

List the 4 hormones used in the mentrual cycle, what they do and what the lead/inhibit release of, what theyre released by

A

FSH- released by pituitary gland

  • causes egg to mature
  • stimulates oestrogen production

Oestrogen- released by ovaries

  • causing lining of uterus to thicken and grow
  • high level stimulates LH surge

LH- by pituaitary gland

  • stimulates ovulation
  • makes follicle develop into corpus luteum
  • corpus luteum secretes progesterone

Progesterone- by corpus luteum after ovulation

  • maintains uturus lining
  • inhibits release of FSH and LH
  • when at low level: lining breaks down and FSH increases
46
Q

How are hormones used in Clomifene to stimulate ovulation

A

By taking clomifene drug you are increasing your FSH and LH levels which stimulate egg maturation and ovulation
the women will then be ovulating and can have intercourse during this time to improve chance of being pregnant

47
Q

How are hormones used in IVF treatment

A
  • person takes FSH and LH before collection so more than 1 egg can be collected
  • collecting eggs from ovaries and fertilising them in a lab with the male sperm
  • when they have grown into embryos one of two are transferred into uterus to improve chance of pregnancy
48
Q

why is maintaining a constant internal environment important

A

because you cells need the right conditions to function properly including rate of enzyme action.
it is dangerous for conditions to vary too much

49
Q

what does the body do if blood glucose levels are too high

A
  • Insulin is secreted by pancreas
  • glucose moves from blood to liver cells
  • insulin makes liver turn glucose into glygogen
50
Q

what does the body do if blood glucose levels are too low

A
  • glucagon is secreted by pancreas,

- glucagon makes liver turn glycogen into glucose

51
Q

What other factors remove glucose from the blood

A

normal metabolism
exercise moves lots of glucose from blood as its used for respiration
excess glucose is stored as glycogen in the liver and muscles or when full as lipids and fat in tissues

52
Q

What does thermoregulation mean

A

process of maintaining an internal temperature for enzymes to work best at
(usually around 37degrees)

53
Q

where is the thermoregulatory center

A

in the hypothalamus in the brain-

conatins receptors which are sensitive to blood temperature in the brain.

54
Q

what does your body do if youre too hot

A
  • erector muscles relax so hairs lie flat and not trapped air and increase air flow on surface
  • lots of sweat is produced in dermis
  • this is released through pores on surface of skin
  • when it evaporates heat is lost to environment
  • blood vessels dilate through vasodilation to allow more blood flow to the surface which cools you
55
Q

what does your body do if youre too cold

A
  • erector muscles contract so hairs trap air to keep you warm
  • little sweat it produced so pores close
  • blood vessels constrict through vasoconstriction so less energy lost to surroundings
  • shivering increases respiration which keeps you warm
56
Q

why is regulating water content important

A

because if levels are too high then water will move into the body cells by osmosis and if theres too much then cells may burst
if too low- water will move out of cells by osmosis and cause cells to shrink

57
Q

which organ helps to regulate body water content and how

3 main roles of the kidney

A

Kidneys-

  • removes urea from blood which is produced by liver from breakdown of amino acids
  • adjust ion levels in the blood
  • adjust water content

they do this by filtering stuff at high pressure and reabsorbing things, waste is carried out in urine

58
Q

What do nephones do

A

filter out certain substances
-liquid part of blood containing urea, ions, water and glucose is forced out of glomerulus and into bowmans capsule at high pressure

59
Q

Explain the water content negative feedback system

A

more water- brain detects pituitary gland releases less ADH, less ADH means kidney reabsorbs less water

less water- brain detects, pituitary releases more ADH ADH makes kidney reabsorb more water

60
Q

How does a kidney dialysis filter blood mechanically

A
  • kidney dialysis machine filters blood for people who have kidney failure
  • done regularly to keep dissolved substances at right concentrations
  • dialysis fluid has the same concentration of glucose and salts as blood plasma
  • the selectively permeable barrier filters out ions and waste substances but not large proteins and cells
61
Q

Describe the pros and cons of a kidney transplant

A

+ lasts forever you dont have to keep having dialysis

  • body can reject the kidney
  • hard to find a donor with a tissue type to match patient
  • can be attacked by antibodies (drugs are taken to reduce this)
62
Q

what is a population

A

all organisms of one species in a habitat

63
Q

what is a community

A

all the organisms of different species living in one habitat

64
Q

How can we study the distribution of small organisms

A

using a quadrat
then take mean total no.oragnsims/ total number of quadrats
-to find population - multiply mean by total area of habitat

65
Q

Name some factors which mean that energy is lost down the food chain

A

lost as heat
not all gets eaten
faeces

66
Q

How do you calculate efficiency in energy levels

A

energy transferred to next level

/ energy transferred at previous level

67
Q

How do human activities affect biodiversity

A

fertilisers can leach into water and cause eutrophication

  • fish farming
  • introducing non-indigenous species
68
Q

How does fish farming reduce biodiversity

A

-food in nets produces large amounts of waste in water
- breeding ground for parasites
-predators attracted and get trapped in nets
-sometimes fish escape and cause problems for indigenous species
(sometimes fish are stored in tanks with low biodiversity as only one species is farmed and free from plants, predators and parasites)

69
Q

How does introducing a non-indigenous species reduce biodiversity

A
  • compete with indigenous species for food and if they out-compete can lead to native species to die out
  • can bring new diseases into habitat
70
Q

Name some ways we can conserve and maintain biodiverisity

A
  • Reforestation- more variety of trees to increase biodiversity and provide food and shelter
  • conservation schemes- protect habitats and species in safe areas and introducing captive breeding programmes and seed banks to distribute rare endangered plants
71
Q

Name some benefits of maintaining biodiversity

name 4

A
  • creates jobs
  • protects human food supply
  • minimal damage to food chains
  • future medicines
  • ecotourism
72
Q

How does increasing consumption of meat and fish affect food security

A
  • overfishing can cause species to die out
  • feeding fish crops that could be eaten by humans
  • less biomass in a food chain
73
Q

How are environmental changes caused by human activity affecting food security

A
  • burning fossil fuels releases CO2 which is a greenhouse gas which leads to global warming
  • climate change reduces crop yield so less food for humans
74
Q

What does food sustainability mean

A

meeting the needs of todays population without affecting the ability of furture populations to meet their needs

75
Q

How do new pests and pathogens affect food security

A

cause damage to crops and livestock

-introduce diseases that can wipe out whole populations of crops can be damaged reducing yield

76
Q

What is reverse Osmosis

A
  • a method of desalination to get rid of impurities from water
  • net movement of water from a lower salt concentration to a higher salt concentration over a partially permeable membrane
77
Q

What is desalination

A

removing salts from salt water to produce potable water
-thermal desalination - salt water boiled in vessel so steam rises and leaves salts and steam condenses down pipe to form water

78
Q

How can farmers increase the amount of nitrates in the soil

A

crop rotation

fertlisers

79
Q

How can cell structures (some) only be seen with an electron microscope but not light microscope?

A

Due to electron microscopes having a higher resolution than light microscopes, it allows us to see greater details of internal structure of mitochondria and chloroplasts.

80
Q

What is the magnification formula? (Total magnification)

A

Eyepiece lens magnification x objective lens magnification.

81
Q

What is magnification formula including sizes?

A

Image size / real size

82
Q

Recall the purposes of sub-cellular structures of: Vacuole

A

Weak solution of sugar and salts and keeps internal structure

83
Q

Recall the purposes of sub-cellular structures of: Ribosomes

A

Translation of genetic material in synthesis of proteins

84
Q

What are the common parts of a bacteria cell?

A

Flagellum to power along away from harmful toxins and towards nutrients and oxygen. Ribosomes, cell membrane, chromosomal DNA, PLasmid DNA for replication (small loops of extra DNA contains genes for drug resistance)

85
Q

How are egg cells adapted to their function?

A
  • Nutrients in cytoplasm feed the embryo
  • Haploid nucleus
  • after fertilisation, membrane changes structure to stop any more sperm getting in so embryo has right amount of DNA
86
Q

How are sperm cells adapted for their function?

A
  • Lots of mitchondria to provide energy for respiration needed to swim the distance
  • Has an acrosome at front of head where enzymes are stroed to break through membrane of the egg cell
  • Haploid nucleus
  • Tail/flagellum to swim to egg
87
Q

What are the substrate concentrations of: Lipids?

A

(Lipases) glycerol and fatty acids

88
Q

What are the substrate concentrations of: Proteins?

A

(Proteases used) amino acids

89
Q

What does an enzyme do?

A

Break down large molecules by speeding up the rate of a reaction for growth and life processes

90
Q

How can we test for proteins in food?

A
  • Biuret Test is used for proteins, first add potassium hydroxide to make it alkaline then add copper sulfate solution (blue)
  • If no protein it stays blue (negative)
  • If there is it turns purple (positive)
91
Q

How can we test for lipids?

A

Emulsion test - Take sample and shake to mix with ethanol for a minute so it dissolved then pour into water

  • Positive = milky emulsion (precipitate)
  • Negative = clear
92
Q

How can we use calorimetry to measure the energy in food?

A
  • First get food sample which burns easily (dry)
  • Weigh the food and skewer it on a needle and hold under boiling tube
  • Add set volume of water to boiling tube and measure initial temperature of water
  • Set fire to food sample and heat boiling tube with it until burnt out
  • Measure water again and use formula:
    Energy in food (J) = Mass of water x temp change x 4.2
93
Q

What is an active site? (Explain the role)

A

Every enzyme has an active site where the substrate joins it to catalyse the reaction. The substrate has to fit into the active site and if it doesn’t fit, the reaction wont be catalysed. This is called a lock and key mechanism.

94
Q

How can we investigate osmosis with potatoes?

A
  • Get sucrose solution in ranging concentration from pure water to very concentrated sucrose
  • Use a potato corer to have evenly sized potato cores
  • Use mass balance to measure mass before then place into test tubes of different concentrations and leave for 40mins
  • Then remove and pat dry and measure mass again (for accuracy)
  • Then work out percentage change = difference mass / original x 100
95
Q

describe the path of substances through the nephon

A 
liquid part of blood forced into glomerelous
then into the bowmans capsule
large molecules (cells+proteins) cant get through
selective reabsorption-glucose, water, ions
96
Q

an indicator species for clean water

A

stonefly larvae, freshwater shrimp

very sensitive to dissolved oxygen

97
Q

an indicator species for dirty water

A

blood worms, sludge worms

98
Q

an indicator species for clean air

A

bushy lichen
blackspot fungus - on rose leaves

-dont like sulphur dioxide

99
Q

an indicator species for dirty air

A

crusty lichen

100
Q

what effects the rate of decomposition

A

temperature- speeds up enzyme reaction
water content- organisms need to water to carry out biological processes
oxygen availability- for aerobic respiration

101
Q

How can we preserve foods

A
  • fridge or freezer to slow down decomposers
  • air tight to stop microoragnsims getting in, then sterilised at high temperature
  • drying with salt removes water so microorganisms die
102
Q

how are ideal conditions maintained in compost bins

A
  • moist warm by decomposers
  • mesh sides to increases oxygen availability
  • insulated

A - Bio last min (1 decks)

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