B3 Flashcards

1
Q

what is a catalyst?

A

a substance that increases the speed of a reaction w/o being changed or used up

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2
Q

what is an enzyme?

A

catalystnmade by living organisms
- biological catalysts

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3
Q

what is an active site?

A

complimentary to substrate causing it to be specific

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4
Q

where does photosynthesis happen?

A

in the leaves
chloroplasts

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5
Q

what factors affect photosynthesis?

A

temperature, light intensity, carbon dioxide concentration

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6
Q

what happens to the RoP if light increases?

A

it increases then plateuas

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7
Q

what happens if RoP plateuas

A

something else is the limiting factor

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8
Q

What happens to RoP if temperature is ow

A

enzymes work more slowly

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9
Q

What factors affect enzyme action?

A

temperature, pH and substrate concentration

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10
Q

wha happens to enzyme action if:
temp is too high
temp is too low

A

high: enyme denatures
low: denatures, not enough energy

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11
Q

what happens to enzyme aaction if
ph is too high
ph is too low

A

denatures for both

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12
Q

what happens to enzyme rate of reaction if substrate concentration is too high or low

A

high: rate of reaction increases until plateaue
low: rate of reaction decreases

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13
Q

what is diffusion?

A

net movement of particles from area of low to high concentration

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14
Q

what does it mean if the cell membrane is partially permeable?

A

only some molecules can diffuse that are small enough
- water, glucose, amino acids

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15
Q

is duffusion passive or active?

A

passive, it doesnt r3equire energy from cell

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16
Q

what is osmosis?

A

net movement of water molecules across a partiallly permeable membrane from a region of low to high concentration

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16
Q

what is osmosis?

A

net movement of water molecules across a partiallly permeable membrane from a region of low to high concentration

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17
Q

what determines water concentration

A

the proportion of water to solutes

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18
Q

what is acyive transport?

A

movement of molecules against their concentration gradient

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19
Q

is active transport active or passive?

A

active, it requires energy from cell

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20
Q

how do mitochondria absorb mineral ions?

A

active transport

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21
Q

why cant plants absorb mineral ions by diffusion?

A

their concentration is higher in the root hair cell than the soil

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22
Q

organ system of a plpant

A

root, stem and leaves

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23
Q

what is the site of photosynthesis?

A

leaves

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24
Q

what is a stomata?

A

holes in the leaf

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25
Q

how does CO2 travel

A

lowwer epidermis(stomata), spongy mesophyll(gaps to diffuse), palisade mesophyll(most of photosynthesis lots of chloroplasts), upper epidermis(almost transparent)

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26
Q

how do plants reduce water loss?

A

waxy cuticle

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27
Q

what are the stomata?

A

openings of gurad cells

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28
Q

why do stomata open for as short as possible?

A

to minimise water loss but maximise CO2 absorption

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29
Q

why do guard cells get turgid?

A

turgid is when they are swollen with water and this is when the stomata open

29
Q

why does the guard cells get flaccid?

A

flaccid is low on water and limp and they close

30
Q

when do stomata close automatically?

A

when water supplies dry up and they are sensitive to light and close at night to save water

30
Q

what cells carry out translocation?

A

phloem

31
Q

what helps the movement of substances in the phloem?

A

holes inbetween cells

32
Q

what direction does the phloem carry things in?

A

any direction

33
Q

what does the phloem do?

A

translocates sugar from photosynthetic tissues to non photosynthetic issue
- leaves to roots

34
Q

how does sugar enter the phloem?

A

through active transport and pushed by water that enters through osmosis

35
Q

what is the zylem made from?

A

dead cells with no ends

36
Q

structure of xylem

A

one long hollow tube

37
Q

what direction does the mineral ions and waater travel in?

A

up

38
Q

what are xylem walls strengtheed in ?

A

lignin

39
Q

what does the xylem do?

A

transports water and mineral ions from roots to leaves

40
Q

what is transpiration?

A

the evaporation of water from leaves

41
Q

what affects transpiration rate?

A

light intensity, temoerature, air movement

41
Q

what affects transpiration rate?

A

light intensity, temoerature, air movement

42
Q

how do plants get healty?

A

by absorbing mineral ions

43
Q

how do plants absorb mineral ions?
diffusion, active transport or osmosis?

A

active transport as there is a high concentration of mineral ions in root hair cells that soil

44
Q

what does a lack of magnesium lead to?

A

yellow leaves as magnesium makes chlorophyll

45
Q

hat does a lack of nitrates lead to?

A

stunted growth as there is a lack of amino acids coding for protein

46
Q

what are carbohydrates, lipids and proteins?

A

biological molecules and nutrients

47
Q

carbohydrates

A
  • made of C, H, O
  • single sugars can join together to make complex carbohydrates
  • broken down by enxzymes in mouth and small intestine
48
Q

proteins

A
  • made of long chains of amino acids
  • made of C, H, O, N
  • broken down in stokmach and small intestine
49
Q

lipids

A
  • made of C, H, O
  • both fats and oils - dependent on temp
  • contain single glycerol mcl attached to fatty acid mcls
  • not polymers- monomers
  • broken down in small intestine
50
Q

how do you test fror sugars?

A

benedicts
* heat in water bath

51
Q

what color will positive benedicts turn?

A

green, yellow, red

52
Q

how do you test for starch?

A

iodine

53
Q

what colour will opositive iodine be?

A

blueish black

54
Q

how do you test for lipids?

A

ethanol/ emulsion test

55
Q

what happens if there is lipids present?

A

milky emulsion forms

56
Q

how to test for proteins?

A

bieurets
* sodium hydroxide and copper sulphate

57
Q

how happens if proteins are present?

A

solution turns purple

58
Q

what happens in the water cycle?

A
  • energy causes water to evaporate
  • water vapour condenses in clouds then water falls back as rain
  • cycle starts again
58
Q

what happens in the water cycle?

A
  • energy causes water to evaporate
  • water vapour condenses in clouds then water falls back as rain
  • cycle starts again
59
Q

what happens in the carbon cycle?

A
  • photosynthesis means CO2 goes into plants which get eaten by animals or passed into atmos
  • when organism die, they decay and release CO2 into the atmos or become fossil fuels which gets burnt by humans
60
Q

what is a population?

A

all organisms of one speiceis in a habitat

61
Q

what is a community?

A

all organisms in one habitat

62
Q

what is an ecosystem?

A

community of organisms and abiotic conditions

63
Q

what is meant by biotic?

A

living factors such as food, number of predators and competion

64
Q

what is meant by abiotic

A

non living factors such as temperature, soil ph and mineral content

65
Q

what is interdependence?

A

all species depend on other species in someway so if something happens to one species, if affects the whole ecosystem

66
Q

what is eutraphication?

A

when a body of water becomes enriched with minerals
- lading to rapid growth of algae whcih builds up on water, blocking sunlight which affects rate of oxygen in water, causing fish and plants to die

67
Q

what is a potometer used for?

A

to measure the rate of transpiration thats proportional to water uptak

68
Q

w can you measure the ecosystem?

A