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Biology GCSE OCR Gateway B > B4 - It's A Green World > Flashcards

B4 - It's A Green World Flashcards

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1
Q

B4 - It’s A Green World

What are the disadvantages of biological control?

A

Predator might not eat pest. May eat useful species. Predators population may increase and get out of control. Predator might not stay in area it is needed.

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2
Q

B4 - It’s A Green World

How can farmers use herbicides to intensively farm?

A

To kill weeds. This means more of Suns energy falling on fields goes to crops and not other competing plants that aren’t wanted.

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3
Q

B4 - It’s A Green World

What does turgid mean?

A

When a plant cell is well watered and plump or swollen.

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4
Q

B4 - It’s A Green World

Temperature - warmer decays faster due to speeding up respiration in microorganism so. Amount of water - faster when moist. Amount of oxygen - decay faster when available, micro organisms need to respire aerobically.

A

What three things does the rate of decay depend on?

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5
Q

B4 - It’s A Green World

How and why do the stomata open and close automatically?

A

Close when water supply in roots dries up. Guard cells have special kidney shape which closes/opens when guard cells become flaccid/turgid. Thin outer walls and thick inner walls makes function properly. Open allows gases for photosynthesis. Sensitive to light - open in day, close night to conserve water

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6
Q

B4 - It’s A Green World

Lots of fertilisers need to be added. No soil to anchor roots and support plant.

A

What are the disadvantages of hydroponics?

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7
Q

B4 - It’s A Green World

What does crenation mean?

A

If a cell loses too much water it completely shrivells up.

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8
Q

B4 - It’s A Green World

What happens to the rate of decay at optimum conditions?

A

Microorganisms grow and reproduce faster meaning there’ll be more of them to decay organisms.

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9
Q

B4 - It’s A Green World

Populations of different species in a habitat

A

What is the community?

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10
Q

B4 - It’s A Green World

Gradual change in distribution of species across a habitat.

A

What is zonation?

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11
Q

B4 - It’s A Green World

What is zonation?

A

Gradual change in distribution of species across a habitat.

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12
Q

B4 - It’s A Green World

What is the population?

A

All organisms of one species in a habitat

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13
Q

B4 - It’s A Green World

What is biodiversity?

A

A measure of variety of life in an area.

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14
Q

B4 - It’s A Green World

Describe a stem cross section…

A

Stems need to resist bending. The xylem forms a sort of ‘scaffolding’. Phloem is always around outside of stem.

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15
Q

B4 - It’s A Green World

Using living things instead of chemicals to control a pest.

A

What is biological control?

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16
Q

B4 - It’s A Green World

Increased light intensity, increased temperature, increased air movement, decrease in air humidity.

A

What 4 factors increase transpiration?

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17
Q

B4 - It’s A Green World

How does adding sugar or salt reduce the rate of decay?

A

If there’s a high concentration of salt or sugar around decomposers they’ll lose water by osmosis. This damages them and mean they can’t work properly. Things like tuna and olives are often stored in brine.

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18
Q

B4 - It’s A Green World

To help enzymes needed for photosynthesis and respiration. If there’s not enough potassium in soil, plants have poor flowers/fruit growth and discoloured leaves.

A

What is potassium useful for in plants?

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19
Q

B4 - It’s A Green World

What are the benefits of transpiration?

A

Constant stream of water keeps plant cool. Provides constant supply of water for photosynthesis. Water creates turgor pressure which helps to support it. Minerals can be brought in.

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20
Q

B4 - It’s A Green World

What is potassium useful for in plants?

A

To help enzymes needed for photosynthesis and respiration. If there’s not enough potassium in soil, plants have poor flowers/fruit growth and discoloured leaves.

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21
Q

B4 - It’s A Green World

Why do plants need magnesium?

A

Magnesium is one of most significant (but not in biggest amounts). Required for making chlorophyll for photosynthesis. Plants without enough magnesium have yellow leaves

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22
Q

B4 - It’s A Green World

Food lasts longer in freezer because decomposers can’t reproduce at all at such low temperatures.

A

How does freezing reduce the rate of decay?

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23
Q

B4 - It’s A Green World

What do Xylem Vessels do?

A

Carry water and minerals from roots up shoot to leaves in transpiration stream.

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24
Q

B4 - It’s A Green World

Loss of water from a plant.

A

What is transpiration?

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25
Q

B4 - It’s A Green World

What controls the stomata and when they open/close?

A

Guard cells

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26
Q

B4 - It’s A Green World

Magnesium is one of most significant (but not in biggest amounts). Required for making chlorophyll for photosynthesis. Plants without enough magnesium have yellow leaves

A

Why do plants need magnesium?

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27
Q

B4 - It’s A Green World

Close when water supply in roots dries up. Guard cells have special kidney shape which closes/opens when guard cells become flaccid/turgid. Thin outer walls and thick inner walls makes function properly. Open allows gases for photosynthesis. Sensitive to light - open in day, close night to conserve water

A

How and why do the stomata open and close automatically?

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28
Q

B4 - It’s A Green World

Making cell walls

A

What is cellulose used for?

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29
Q

B4 - It’s A Green World

Square frame allows you to study a small area and scale up findings to make an estimate for a larger area.

A

What is a quadrat used for?

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30
Q

B4 - It’s A Green World

Why are organic fertilisers used?

A

Recycles nutrients left in plants and animal waste. Doesn’t work as well as artificial fertiliser but better for environment.

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31
Q

B4 - It’s A Green World

Physically removing weeds rather than spraying herbicide. More labour intensive but no chemicals involved.

A

How does weeding help organic farmers?

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32
Q

B4 - It’s A Green World

What methods are used to reduce the rate of decay?

A

Canning, cooling, freezing, drying, adding salt/sugar, and adding vinegar.

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33
Q

B4 - It’s A Green World

Upper epidermis, palisade mesophyll layer, spongy mesophyll layer and lower epidermis

A

What are the four layers in a leaf?

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34
Q

B4 - It’s A Green World

Number of 1st sample x number in 2nd sample ÷ number in 2nd sample previously marked

A

How do you calculate population size?

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35
Q

B4 - It’s A Green World

Guard cells

A

What controls the stomata and when they open/close?

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36
Q

B4 - It’s A Green World

What are the advantages of hydroponics?

A

Mineral levels can be controlled more accurately. Disease can be controlled more effectively.

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37
Q

B4 - It’s A Green World

Woodlands and lakes

A

Give two examples of natural eco systems…

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38
Q

B4 - It’s A Green World

Another method of intensive farming where plants are grown in nutrient solutions instead of soil. Often used to grow glasshouse tomatoes on commercial scale, as well as grow plants in areas with barren soil.

A

What is hydroponics?

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39
Q

B4 - It’s A Green World

No changes in population size due to deaths, immigration or emigration. Sampling method was set up same way each time. Markings haven’t affected animal’s chance of survival.

A

What assumptions have to be made when using capture and recapture?

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40
Q

B4 - It’s A Green World

What are the advantages of biological control?

A

No chemicals used, so less pollution, disruption to food chains and risk to people. No need to keep repeating treatment.

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41
Q

B4 - It’s A Green World

What assumptions have to be made when using capture and recapture?

A

No changes in population size due to deaths, immigration or emigration. Sampling method was set up same way each time. Markings haven’t affected animal’s chance of survival.

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42
Q

B4 - It’s A Green World

What is active transport?

A

Uses energy from respiration to help plant pull minerals into root hair against concentration gradient - from low concentrations to high concentrations.

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43
Q

B4 - It’s A Green World

Growing crops in cycle. Stops pest and diseases for one crop building up - stops nutrients running out. Most crop rotations include nitrogen fixing crop like legumes - put nitrates back into soil.

A

What is crop rotation in organic farming?

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44
Q

B4 - It’s A Green World

How does cooling reduce the rate of decay?

A

Putting food in a fridge slows down decay because it slows decomposers’ reproduction rate.

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45
Q

B4 - It’s A Green World

What is a plasmolysed cell?

A

If plant is short of water, cytoplasm starts to shrink and membrane pulls away from cell wall - but inelastic cell wall keeps things in position, just droops a bit.

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46
Q

B4 - It’s A Green World

What three things does the rate of decay depend on?

A

Temperature - warmer decays faster due to speeding up respiration in microorganism so. Amount of water - faster when moist. Amount of oxygen - decay faster when available, micro organisms need to respire aerobically.

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47
Q

B4 - It’s A Green World

What does Flaccid mean?

A

When a plant doesn’t get enough water from soil, plant begins to wilt because turgid pressure no longer there.

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48
Q

B4 - It’s A Green World

Give two examples of natural eco systems…

A

Woodlands and lakes

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49
Q

B4 - It’s A Green World

Feed on dead and decaying material (detritus). Examples include earthworms, maggots, and wood lice. As these feed on decaying material, they break it up into smaller pieces to give a bigger surface area to speed up decay.

A

What are detritivores?

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50
Q

B4 - It’s A Green World

What is the term for non-living conditions?

A

Abiotic

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51
Q

B4 - It’s A Green World

Abiotic

A

What is the term for non-living conditions?

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52
Q

B4 - It’s A Green World

How is a disease used in biological control?

A

Myxomatosis - disease which kills rabbits. Myxoma virus released in Australia as biological control when rabbit population grew out of control and ruined crops.

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53
Q

B4 - It’s A Green World

For storing in seeds

A

What are lipids used for?

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54
Q

B4 - It’s A Green World

What happens in transpiration?

A

Caused by evaporation and diffusion of water vapour inside leaves. Creates shortage of water in leaf so more water is drawn up through xylem vessels. More water is drawn up through roots so there is a constant transpiration stream through plant.

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55
Q

B4 - It’s A Green World

What are detritivores?

A

Feed on dead and decaying material (detritus). Examples include earthworms, maggots, and wood lice. As these feed on decaying material, they break it up into smaller pieces to give a bigger surface area to speed up decay.

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56
Q

B4 - It’s A Green World

Organic farmers use less chemicals. Better for environment, less chance of river pollution - no use of pesticides = less wildlife harm. To be classed as organic it needs to follow ethical treatment of animals. No battery farming.

A

What are the advantages of organic farming?

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57
Q

B4 - It’s A Green World

They let carbon dioxide out and oxygen in, whilst also allowing water to escape (transpiration).

A

How does having stomata adapt a plant for photosynthesis?

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58
Q

B4 - It’s A Green World

Transport food - mainly sugars - both up and down stem to growing and storing tissues - movement is known as translocation.

A

What do phloem tubes do?

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59
Q

B4 - It’s A Green World

Vinegar is acidic ad acid kills decomposers.

A

How does adding vinegar reduce the rate of decay?

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60
Q

B4 - It’s A Green World

Describe a root cross section…

A

Roots have to resist crushing as they push through soil. Xylem in centre to give it strength.

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61
Q

B4 - It’s A Green World

Predator might not eat pest. May eat useful species. Predators population may increase and get out of control. Predator might not stay in area it is needed.

A

What are the disadvantages of biological control?

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62
Q

B4 - It’s A Green World

What are saprophytes?

A

Feed on decaying material by extracellular digestion which means they excrete digestive enzymes on material outside their cells. Enzyme breaks down material into smaller bits which can be absorbed by saprophyte. Many are fungi.

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63
Q

B4 - It’s A Green World

Why is glucose turned into starch?

A

It can’t dissolve and move away from storage areas in solution. It doesn’t affect water concentration inside cells - soluble substances would bloat storage cells by drawing in water.

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64
Q

B4 - It’s A Green World

A measure of variety of life in an area.

A

What is biodiversity?

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65
Q

B4 - It’s A Green World

Canning, cooling, freezing, drying, adding salt/sugar, and adding vinegar.

A

What methods are used to reduce the rate of decay?

66
Q

B4 - It’s A Green World

What 3 main minerals do plants need?

A

Nitrates, phosphates and potassium (magnesium in small doses)

67
Q

B4 - It’s A Green World

Respiration, converts it into cellulose, starch, lipids and it is combined with nitrates to make proteins.

A

What do plants use glucose for?

68
Q

B4 - It’s A Green World

Large surface area allows gases to diffuse

A

How does being broad adapt a plant for photosynthesis?

69
Q

B4 - It’s A Green World

Sowing seeds later or earlier in season will avoid major pests for that crop. Farmers won’t need to use pesticides.

A

How does varying seed plant times help organic farming?

70
Q

B4 - It’s A Green World

All organisms of one species in a habitat

A

What is the population?

71
Q

B4 - It’s A Green World

How can farmers use pesticides to intensively farm?

A

Kills insects that eat crop. This makes sure no energy is transferred into a different food chain. It’s all saved for growing crops.

72
Q

B4 - It’s A Green World

Roots have to resist crushing as they push through soil. Xylem in centre to give it strength.

A

Describe a root cross section…

73
Q

B4 - It’s A Green World

What is biological control?

A

Using living things instead of chemicals to control a pest.

74
Q

B4 - It’s A Green World

Putting food in a fridge slows down decay because it slows decomposers’ reproduction rate.

A

How does cooling reduce the rate of decay?

75
Q

B4 - It’s A Green World

All organisms living in a particular area as well as non-living conditions such as temperature, salinity and soil quality.

A

What is an eco system?

76
Q

B4 - It’s A Green World

How can capture and recapture be used to estimate population size?

A

Capture a sample of population, mark animals harmlessly and release them. Recapture another sample and count how many have marks. Estimate population size using equation.

77
Q

B4 - It’s A Green World

How do you calculate population size?

A

Number of 1st sample x number in 2nd sample ÷ number in 2nd sample previously marked

78
Q

B4 - It’s A Green World

Carry water and minerals from roots up shoot to leaves in transpiration stream.

A

What do Xylem Vessels do?

79
Q

B4 - It’s A Green World

What does lysis mean?

A

If an animal cell takes in too much water it bursts.

80
Q

B4 - It’s A Green World

Animals are kept close together indoors in small pens so they are warm and can’t move about. Saves them wasting energy as they move around, and stops them using up so much energy keeping warm.

A

How can farmers use battery farming to intensively farm?

81
Q

B4 - It’s A Green World

Myxomatosis - disease which kills rabbits. Myxoma virus released in Australia as biological control when rabbit population grew out of control and ruined crops.

A

How is a disease used in biological control?

82
Q

B4 - It’s A Green World

How does drying reduce the rate of decay?

A

Dried food lasts longer because decomposers need water to carry out cell reactions. Lots of fruits are preserved by drying them out, and sometimes meat is too.

83
Q

B4 - It’s A Green World

To kill weeds. This means more of Suns energy falling on fields goes to crops and not other competing plants that aren’t wanted.

A

How can farmers use herbicides to intensively farm?

84
Q

B4 - It’s A Green World

What do plants use glucose for?

A

Respiration, converts it into cellulose, starch, lipids and it is combined with nitrates to make proteins.

85
Q

B4 - It’s A Green World

How does being thin adapt a plant for photosynthesis?

A

Carbon dioxide and water vapour only have to diffuse a short distance to reach photosynthesising cells.

86
Q

B4 - It’s A Green World

Certain types of wasps and flies produce larvae which develop on/inside host insect. Eventually kills insect host. Lots of insects have parasites like this.

A

How is a parasite used in biological control?

87
Q

B4 - It’s A Green World

Kills insects that eat crop. This makes sure no energy is transferred into a different food chain. It’s all saved for growing crops.

A

How can farmers use pesticides to intensively farm?

88
Q

B4 - It’s A Green World

It can’t dissolve and move away from storage areas in solution. It doesn’t affect water concentration inside cells - soluble substances would bloat storage cells by drawing in water.

A

Why is glucose turned into starch?

89
Q

B4 - It’s A Green World

How does having air spaces benefit a leaf for photosynthesis?

A

In spongy mesophyll layer and allow gases like carbon dioxide and oxygen to move between stomata and photosynthesising cells. Means there is a larger surface area for gas exchange - big internal surface area to volume ratio.

90
Q

B4 - It’s A Green World

Contain nitrogen for making amino acids and proteins. Needed for cell growth. If a plant can’t get enough nitrates, its growth will be poor and it will have yellow older leaves.

A

Why are nitrates useful for plants?

91
Q

B4 - It’s A Green World

Why does having guard cells adapt a plant for photosynthesis?

A

They surround stomata and control when they open and close. This allows guard cells to control gas exchange.

92
Q

B4 - It’s A Green World

Needed for respiration and growth. Contain phosphorous for making DNA and cell membranes. Plants without enough phosphate have poor root growth and discoloured older leaves.

A

What are phosphates useful for in plants?

93
Q

B4 - It’s A Green World

Trying to produce as much food as possible from land, animals and plants.

A

What is intensive farming?

94
Q

B4 - It’s A Green World

When a plant doesn’t get enough water from soil, plant begins to wilt because turgid pressure no longer there.

A

What does Flaccid mean?

95
Q

B4 - It’s A Green World

How does weeding help organic farmers?

A

Physically removing weeds rather than spraying herbicide. More labour intensive but no chemicals involved.

96
Q

B4 - It’s A Green World

Mineral levels can be controlled more accurately. Disease can be controlled more effectively.

A

What are the advantages of hydroponics?

97
Q

B4 - It’s A Green World

Nitrates, phosphates and potassium (magnesium in small doses)

A

What 3 main minerals do plants need?

98
Q

B4 - It’s A Green World

They surround stomata and control when they open and close. This allows guard cells to control gas exchange.

A

Why does having guard cells adapt a plant for photosynthesis?

99
Q

B4 - It’s A Green World

What are the disadvantages of hydroponics?

A

Lots of fertilisers need to be added. No soil to anchor roots and support plant.

100
Q

B4 - It’s A Green World

What is transpiration?

A

Loss of water from a plant.

101
Q

B4 - It’s A Green World

What are the main effects of intensive farming?

A

1) removal of hedges destroys natural habitat and can lead to soil erosion. 2) fertilisers can cause eutrophication 3) pesticides disturb food chain 4) people believe it is cruel to animals.

102
Q

B4 - It’s A Green World

If an animal cell takes in too much water it bursts.

A

What does lysis mean?

103
Q

B4 - It’s A Green World

How does being broad adapt a plant for photosynthesis?

A

Large surface area allows gases to diffuse

104
Q

B4 - It’s A Green World

What is the word equation for respiration?

A

glucose + oxygen → carbon dioxide + water

105
Q

B4 - It’s A Green World

Microorganisms grow and reproduce faster meaning there’ll be more of them to decay organisms.

A

What happens to the rate of decay at optimum conditions?

106
Q

B4 - It’s A Green World

What is osmosis?

A

Net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

107
Q

B4 - It’s A Green World

What is intensive farming?

A

Trying to produce as much food as possible from land, animals and plants.

108
Q

B4 - It’s A Green World

How is a parasite used in biological control?

A

Certain types of wasps and flies produce larvae which develop on/inside host insect. Eventually kills insect host. Lots of insects have parasites like this.

109
Q

B4 - It’s A Green World

glucose + oxygen → carbon dioxide + water

A

What is the word equation for respiration?

110
Q

B4 - It’s A Green World

By osmosis - root cells grow ‘hairs’ which stick out into soil. Microscopic hairs give plant a large surface area for absorbing water. Usually a high concentration of water in soil so water is drawn in.

A

How do root hairs take in water?

111
Q

B4 - It’s A Green World

Dried food lasts longer because decomposers need water to carry out cell reactions. Lots of fruits are preserved by drying them out, and sometimes meat is too.

A

How does drying reduce the rate of decay?

112
Q

B4 - It’s A Green World

What are phosphates useful for in plants?

A

Needed for respiration and growth. Contain phosphorous for making DNA and cell membranes. Plants without enough phosphate have poor root growth and discoloured older leaves.

113
Q

B4 - It’s A Green World

What adaptations do plants have to reduce water loss?

A

Waxy cuticle covering upper epidermis, helps make upper side waterproof. Stomata found on lower surface where it’s darker/cooler - slows diffusion. Bigger/more stomata = more water lost so in hot climates have fewer and smaller stomata.

114
Q

B4 - It’s A Green World

How can farmers use battery farming to intensively farm?

A

Animals are kept close together indoors in small pens so they are warm and can’t move about. Saves them wasting energy as they move around, and stops them using up so much energy keeping warm.

115
Q

B4 - It’s A Green World

carbon dioxide + water → glucose + oxygen 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

A

What are the equations for photosynthesis?

116
Q

B4 - It’s A Green World

If animal doesn’t change its prey due to a food shortage, at risk of bio accumulation with pesticide as quantities increase up food chain.

A

How do pesticides disturb food chains?

117
Q

B4 - It’s A Green World

Waxy cuticle covering upper epidermis, helps make upper side waterproof. Stomata found on lower surface where it’s darker/cooler - slows diffusion. Bigger/more stomata = more water lost so in hot climates have fewer and smaller stomata.

A

What adaptations do plants have to reduce water loss?

118
Q

B4 - It’s A Green World

If there’s a high concentration of salt or sugar around decomposers they’ll lose water by osmosis. This damages them and mean they can’t work properly. Things like tuna and olives are often stored in brine.

A

How does adding sugar or salt reduce the rate of decay?

119
Q

B4 - It’s A Green World

Recycles nutrients left in plants and animal waste. Doesn’t work as well as artificial fertiliser but better for environment.

A

Why are organic fertilisers used?

120
Q

B4 - It’s A Green World

What are the four layers in a leaf?

A

Upper epidermis, palisade mesophyll layer, spongy mesophyll layer and lower epidermis

121
Q

B4 - It’s A Green World

Carbon dioxide and water vapour only have to diffuse a short distance to reach photosynthesising cells.

A

How does being thin adapt a plant for photosynthesis?

122
Q

B4 - It’s A Green World

What do phloem tubes do?

A

Transport food - mainly sugars - both up and down stem to growing and storing tissues - movement is known as translocation.

123
Q

B4 - It’s A Green World

How does having stomata adapt a plant for photosynthesis?

A

They let carbon dioxide out and oxygen in, whilst also allowing water to escape (transpiration).

124
Q

B4 - It’s A Green World

Using active transport. Root hairs give a big surface area but concentration of minerals in soil is low. Normal diffusion doesn’t happen but active transport does.

A

How do root hairs take in minerals?

125
Q

B4 - It’s A Green World

What is crop rotation in organic farming?

A

Growing crops in cycle. Stops pest and diseases for one crop building up - stops nutrients running out. Most crop rotations include nitrogen fixing crop like legumes - put nitrates back into soil.

126
Q

B4 - It’s A Green World

E.g. Aphids are pest - eat vegetables and roses. Ladybirds predate aphids so people release them on fields and gardens to keep numbers down.

A

How is a predator used in biological control?

127
Q

B4 - It’s A Green World

No chemicals used, so less pollution, disruption to food chains and risk to people. No need to keep repeating treatment.

A

What are the advantages of biological control?

128
Q

B4 - It’s A Green World

Net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

A

What is osmosis?

129
Q

B4 - It’s A Green World

In spongy mesophyll layer and allow gases like carbon dioxide and oxygen to move between stomata and photosynthesising cells. Means there is a larger surface area for gas exchange - big internal surface area to volume ratio.

A

How does having air spaces benefit a leaf for photosynthesis?

130
Q

B4 - It’s A Green World

How is a predator used in biological control?

A

E.g. Aphids are pest - eat vegetables and roses. Ladybirds predate aphids so people release them on fields and gardens to keep numbers down.

131
Q

B4 - It’s A Green World

Feed on decaying material by extracellular digestion which means they excrete digestive enzymes on material outside their cells. Enzyme breaks down material into smaller bits which can be absorbed by saprophyte. Many are fungi.

A

What are saprophytes?

132
Q

B4 - It’s A Green World

How does varying seed plant times help organic farming?

A

Sowing seeds later or earlier in season will avoid major pests for that crop. Farmers won’t need to use pesticides.

133
Q

B4 - It’s A Green World

1) removal of hedges destroys natural habitat and can lead to soil erosion. 2) fertilisers can cause eutrophication 3) pesticides disturb food chain 4) people believe it is cruel to animals.

A

What are the main effects of intensive farming?

134
Q

B4 - It’s A Green World

What is a quadrat used for?

A

Square frame allows you to study a small area and scale up findings to make an estimate for a larger area.

135
Q

B4 - It’s A Green World

What are the advantages of organic farming?

A

Organic farmers use less chemicals. Better for environment, less chance of river pollution - no use of pesticides = less wildlife harm. To be classed as organic it needs to follow ethical treatment of animals. No battery farming.

136
Q

B4 - It’s A Green World

How do root hairs take in minerals?

A

Using active transport. Root hairs give a big surface area but concentration of minerals in soil is low. Normal diffusion doesn’t happen but active transport does.

137
Q

B4 - It’s A Green World

What is the community?

A

Populations of different species in a habitat

138
Q

B4 - It’s A Green World

Capture a sample of population, mark animals harmlessly and release them. Recapture another sample and count how many have marks. Estimate population size using equation.

A

How can capture and recapture be used to estimate population size?

139
Q

B4 - It’s A Green World

How do root hairs take in water?

A

By osmosis - root cells grow ‘hairs’ which stick out into soil. Microscopic hairs give plant a large surface area for absorbing water. Usually a high concentration of water in soil so water is drawn in.

140
Q

B4 - It’s A Green World

What is cellulose used for?

A

Making cell walls

141
Q

B4 - It’s A Green World

Why are nitrates useful for plants?

A

Contain nitrogen for making amino acids and proteins. Needed for cell growth. If a plant can’t get enough nitrates, its growth will be poor and it will have yellow older leaves.

142
Q

B4 - It’s A Green World

How do pesticides disturb food chains?

A

If animal doesn’t change its prey due to a food shortage, at risk of bio accumulation with pesticide as quantities increase up food chain.

143
Q

B4 - It’s A Green World

If plant is short of water, cytoplasm starts to shrink and membrane pulls away from cell wall - but inelastic cell wall keeps things in position, just droops a bit.

A

What is a plasmolysed cell?

144
Q

B4 - It’s A Green World

What are the equations for photosynthesis?

A

carbon dioxide + water → glucose + oxygen 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

145
Q

B4 - It’s A Green World

Caused by evaporation and diffusion of water vapour inside leaves. Creates shortage of water in leaf so more water is drawn up through xylem vessels. More water is drawn up through roots so there is a constant transpiration stream through plant.

A

What happens in transpiration?

146
Q

B4 - It’s A Green World

Uses energy from respiration to help plant pull minerals into root hair against concentration gradient - from low concentrations to high concentrations.

A

What is active transport?

147
Q

B4 - It’s A Green World

What 4 factors increase transpiration?

A

Increased light intensity, increased temperature, increased air movement, decrease in air humidity.

148
Q

B4 - It’s A Green World

How does freezing reduce the rate of decay?

A

Food lasts longer in freezer because decomposers can’t reproduce at all at such low temperatures.

149
Q

B4 - It’s A Green World

How does canning reduce the rate of decay?

A

Food in an airtight can keeps decomposers out.

150
Q

B4 - It’s A Green World

What is hydroponics?

A

Another method of intensive farming where plants are grown in nutrient solutions instead of soil. Often used to grow glasshouse tomatoes on commercial scale, as well as grow plants in areas with barren soil.

151
Q

B4 - It’s A Green World

What are lipids used for?

A

For storing in seeds

152
Q

B4 - It’s A Green World

Describe a leaf cross section…

A

In a leaf xylem and phloem together make up a network of veins. These are needed to support leaves.

153
Q

B4 - It’s A Green World

When a plant cell is well watered and plump or swollen.

A

What does turgid mean?

154
Q

B4 - It’s A Green World

What is an eco system?

A

All organisms living in a particular area as well as non-living conditions such as temperature, salinity and soil quality.

155
Q

B4 - It’s A Green World

Constant stream of water keeps plant cool. Provides constant supply of water for photosynthesis. Water creates turgor pressure which helps to support it. Minerals can be brought in.

A

What are the benefits of transpiration?

156
Q

B4 - It’s A Green World

How does adding vinegar reduce the rate of decay?

A

Vinegar is acidic ad acid kills decomposers.

157
Q

B4 - It’s A Green World

Food in an airtight can keeps decomposers out.

A

How does canning reduce the rate of decay?

158
Q

B4 - It’s A Green World

In a leaf xylem and phloem together make up a network of veins. These are needed to support leaves.

A

Describe a leaf cross section…

159
Q

B4 - It’s A Green World

If a cell loses too much water it completely shrivells up.

A

What does crenation mean?

160
Q

B4 - It’s A Green World

Net movement of particles from an area of higher concentration to an area of lower concentration.

A

What is diffusion?

161
Q

B4 - It’s A Green World

Stems need to resist bending. The xylem forms a sort of ‘scaffolding’. Phloem is always around outside of stem.

A

Describe a stem cross section…

162
Q

B4 - It’s A Green World

What is diffusion?

A

Net movement of particles from an area of higher concentration to an area of lower concentration.

Biology GCSE OCR Gateway B (6 decks)

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