Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A level biology > energy transfers in and between organisms P2 > Flashcards

energy transfers in and between organisms P2 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what is the role of light in photoionisation in the light dependent stage of photosynthesis

A

chlorophyll molecules absorb energy from photons of light. this Excites the electrons (raising their energy level) causing them to be released (lost) from the chlorophyll (and go down ETC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 2 main stages involved in ATP production in light-dependent reaction?

A

electron transfer chain
chemiosmosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what happens in the electron transfer chain?

A

electrons released from chlorophyll move down a series of carrier proteins embedded in thylakoid membrane and undergo a series of redox reactions which releases energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how is proton concentration gradient established during chemiosmosis?

A

some energy released from ETC is coupled to active transport of protons from stroma into thylakoid space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how does chemiosmosis produce ATP in light-dependent reaction?

A

protons move down concentration gradient from thylakoid space into stroma through ATP synthase.

ATP synthase catalyses ADP+Pi—>ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

explain the role of light in photolysis

A

light energy splits water molecules into protons, electrons and oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens to the products of photolysis of water?

A

protons move out of thylakoid space via ATP synthase and are used to reduce the coenzyme NAPD

electrons replace electrons lost from chlorophyll

oxygen is used for respiration and diffuses out of leaf as waste gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how and where is reduced NADP produced in the light dependent reaction?

A

NADP + proton + electron —> reduced NADP
catalysed by dehydrogenase enzymes
in stroma of chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

where do the H+ ions and electrons to reduce NADP come from?

A

H+ ions - photolysis of water
electrons - NADP acts as the final electron acceptor of the electron transfer chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe what happens during photoionisation in the light-dependent reaction

A

chlorophyll absorbs light, which excites elections causing electrons to be lost.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

name the three main stages in the calvin cycle

A

carbon fixation
reduction
regeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what happens during carbon fixation?

A

reaction between carbon dioxide and RuBP (ribulose biphosphate)

forms unstable 6 carbon molecule (2x GP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what happens during reduction in the calvin cycle?

A

2 x GP is reduced to 2 x TP (triose phosphate) which requires reduced NADP and ATP for energy.

forms NADP and ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how does the light- independent reaction result in the production of useful organic substances

A

one carbon leaves the cycle

6 cycles to make glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what happens during regeneration in the calvin cycle?

A

after 1C leaves the cycle, 5C is used to regenerate RuBP using ATP

(ATP—>ADP +Pi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

state the roles of ATP and NADPH in the light independent reaction

A

ATP: reduction of GP to TP and provides energy to regenerate RuBP

NADPH: coenzyme transports electrons needed for the reduction of GP to TP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the structure of a chloroplast

A

usually disc shaped, double membrane

thylakoids - flattened discs stack to form grana

lamellae- tubular extensions attach thylakoids in adjacent grana

stroma - fluid-filled matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does the structure of the chloroplast maximise the rate of the light dependent reaction?

A

ATP synthase channels within granal membrane

large surface area of thylakoid membrane for electron transport chain.

photosystems position chlorophyll to enable maximum absorption of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how does the structure of the chloroplast maximise the rate of the light independent reaction?

A

own DNA and ribosomes for synthesis of enzymes (rubisco)

concentration of enzymes and substrates in stroma is high.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

define limiting factor

A

factor that determines maximum rate of a reaction, even if other factors change to become more favourable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

name 4 environmental factors that could limit the rate of photosynthesis

A

light intensity (light dependent stage)

CO2 levels (light independent stage)

temperature (enzyme controlled steps)

mineral/ magnesium levels (maintain normal functioning of chlorophyll)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

outline some common agricultural practices used to overcome the effect of limiting factors in photosynthesis

A

artificial light, especially at night

artificial heating

addition of CO2 to greenhouse atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

why do farmers try to overcome the effect of limiting factors?

A

to increase yield

additional cost must be balanced with yield to ensure maximum profit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

as light is increased, it then plateaus. explain why

A

all NADP has become reduced from the non-cyclic photophosphorylation (light-dependent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

as CO2 concentration increases, so does photosynthesis up to a point. why does it stop increasing?

A

no more RuBP available as all combines with CO2 or no more rubisco (all have formed ES complexes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

as temperature increases, so does photosynthesis, up to a point. explain why it stops increasing

A

changed to tertiary structure of ATP synthase/ rubisco

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

name the four main stages in aerobic respiration and where they occur

A

glycolysis - cytoplasm

link reaction - mitochondrial matrix

Krebs cycle - mitochondrial matrix

oxidative phosphorylation - cristae

28
Q

describe the process of glycolysis

A
  • glucose is phosphorylated using ATP to form hexose biphosphate
  • this splits to form 2x triose phosphate
  • 2x TP is oxidised to form pyruvate
  • net gain of 2x reduced NAD and 2x ATP per glucose
29
Q

outline the stages of the link reaction

A
  • pyruvate is oxidised/ decarboxylated to acetate (NAD reduced)
  • acetate combines with coenzyme A to form acetyl-coenzyme A

produces 2Co2, 2NADH and 2Acetyl coeunzyme A

30
Q

give a summary equation for the link reaction

A

pyruvate + NAD + CoA —> acetyl CoA + NADH + CO2

31
Q

outline the stages of the Krebs cycle

A
  • acetyl CoA (2C) combines with oxaloacetate (4C) to form citrate (6c)
  • CoA is released back to the link reaction to combine with acetate again
  • citrate is decarboxilated, NAD is reduced and ATP is used for energy (ADP+pi)
  • decarboxilated again to reform oxaloacetate. NAD is reduced and so is FAD
32
Q

what is the electron transfer chain?
(oxidative phosphorylation)

A

series of carrier proteins embedded in membrane of the cristae of mitochondria

produces ATP through oxidative phosphorylation via chemiosmosis during aerobic respiration

33
Q

what happens in the electron transfer chain (oxidative phosphorylation)

A

electrons released from NAD and FAD undergo redox reactions.

the energy released maintains a proton gradient (protons move from matrix to cristae)

oxygen acts as a final electron acceptor

34
Q

how is a proton gradient established during chemiosmosis in aerobic respiration?

A

some energy released from the ETC is coupled to the active transport of H+ ions from the mitochondrial matrix to the cristae

35
Q

how does chemiosmosis produce ATP during aerobic respiration?

A

H+ ions move down the electrochemical gradient from the cristae to the matrix via ATP synthase

ATP synthase catalyses ADP+Pi —> ATP

36
Q

state the role of oxygen in aerobic respiration

A

final electron acceptor in ETC (produces water)

37
Q

what is the benefit of an electron transport chain rather than a single reaction?

A

energy is released gradually

less energy is released as heart

38
Q

name 2 types of molecule that can be used as alternative respiratory substrates

A

proteins

lipids

39
Q

what happens during anaerobic respiration in animals?

A

pyruvate +NADH —> lactate +NAD

40
Q

what happens in anaerobic respiration in plants and yeast cells?

A

pyruvate is decarboxilated to form ethanal.

ethanal is reduced to ethanol using NADH to produce oxidised NAD for further glycolysis

41
Q

what’s the advantage of producing ethanol/ lactate during anaerobic respiration?

A

regenerates/ produces NAD so glycolysis can continue

42
Q

compare aerobic and anaerobic respiration

A

both involve glycolysis
both require NAD
both produce ATP

43
Q

describe the advantage of the bohr effect during intense exercise

A

increases dissociation of oxygen
for aerobic respiration at the tissues/muscles/cells

44
Q

how do plants use the sugars from photosynthesis?

A
  • primarily as respiratory substrates
  • to synthesise other biological molecules e.g. cellulose
45
Q

what is biomass?

A

total dry mass of tissue or mass of carbon per given area and time

46
Q

how can the chemical energy store in dry biomass be estimated?

A

using Calorimetry

47
Q

how could a student ensure that all water had been removed from a sample before weighing?

A

heat the sample and reweigh it until the mass reading is constant

48
Q

give the formula showing the relationship between GPP and NPP

A

NPP = GPP - R

R = respiratory losses.

49
Q

define gross primary production (GPP)

A

Total chemical energy in plant biomass within a given volume or area

50
Q

define net primary productivity(NPP)

A

chemical energy store in plant biomass after respiratory losses to the environment have been taken into account

51
Q

why is most of the suns every not converted to organic matter?

A

most solar energy absorbed by atmosphere or reflected in clouds.

photosynthetic pigments cannot absorb some wavelengths of light.

energy is lost as heat during respiration/photosynthesis.

52
Q

how can the net production of consumers (N) be calculated?

A

N = I - (F+R)

I = chemical energy lost by ingested food
F= chemical energy lost by faeces.
R= respiratory losses to environment.

53
Q

why does biomass decrease along a food chain?

A
  • energy lost in urine and faeces.
  • some of the organism isn’t consumed
  • energy lost to surroundings as heat.
54
Q

define primary and secondary productivity

A
  • rate of primary/ secondary production.
  • measured by biomass in a specific area over a given time period.
55
Q

outline some common farming practices used to increase the efficiency of energy transfer

A
  • simplifying food webs (exclusion of predators) to reduce energy lost to non-human food chains
  • artificial heating: reduce energy lost to maintain constant body temperature.
56
Q

give the equation for % efficiency

A

energy converted to a useful form/
total energy supplied x100

57
Q

explain why the length of food chains is limited

A

energy is lost at each trophic level
so there is insufficient energy to support a higher trophic level.

58
Q

name the 4 main stages of the nitrogen cycle

A

nitrogen fixation
ammonification
nitrification
denitrification

59
Q

outline the role of bacteria in nitrogen fixation

A

nitrogen fixing bacteria consume nodules of legumes for energy.

60
Q

outline the role of bacteria ammonification

A

saprobionts

61
Q

suggest an advantage of having different coloured pigments in leaves

A

different wavelengths of light for photosynthesis

62
Q

explain why a decrease in the light-dependent reaction leads to a decrease in the light-independent reaction.

A

less ATP
less reduces NADP

63
Q

explain why a decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis

A

less carbon dioxide reacts with RUBP, so less GP.

64
Q

in natural ecosystems, most of the light falling in producers is n it used in photosynthesis, suggest 2 reasons why

A

light is reflected

light is wrong wavelength

(CO2 concentration/ temp are limiting factors)

65
Q

describe the role of saprobionts in the nitrogen cycle

A

decompose proteins which produces ammonium

A level biology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions