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Aqa a level biology > Topic 5: energy transfers between organisms > Flashcards

Topic 5: energy transfers between organisms Flashcards

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1
Q

describe the function of a chloroplast

A

where photosynthesis ocuurs
-thykaloid discs containing chlorophyll absorb light to produce carbohydrates and sugars

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2
Q

features of chloroplasts

A

-Features of chloroplasts –> starch grain, ribosomes (70S), outer and inner membrane, stroma, thykaloid, granum

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3
Q

thykaloid

A

Thykaloid –> contains chlorophyll and absorbs light

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4
Q

starch grain

A

Starch grain –> stores polymers of glucose

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5
Q

lamellae

A

Lamellae –> proteins that hold granum in optimum position to absorb light

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6
Q

absorbance and reflection by chlorophyll

A

Chlorophyll reflect green light and absorbs all other colours such as red

Accessory pigment –> maximize the amount of pigment that can be absorbed e.g carotenoids

-chlorophyll is a mixture of pigments each absorbing different wavelengths of light

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7
Q

Describe how you would present the data in the table as a graph

A

discrete data (distinct groups) = bar chart with standard deviation lines

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8
Q

In leaves at the top of trees in a forest. CO2 is often the limiting factor for photosynthesis. Explain why

A

-light = not limiting as there is now shading
-temperature = not limiting as no shading (fast reactions of enzymes in LDR)

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9
Q

structure of chloroplasts

A

Grana –> the stacked collection of thykaloid discs

-Thykaloid –> a small membrane bound sac or disc containing chloropyll

-Stroma –> a fluid filled space within the chloroplast containing an abnormally high concentration of protons (H+)

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10
Q

light dependent reaction

A

1) the first photosystem recieves light energy from the sun and uses this for photolysis (breaking w light) of water into H+ ions, O2 and electrons

2) The electrons are elevated to a high energy state allowing them to move through the photosystems giving energy to each membrane protein. It eventually recieves and is accepted by an electron accepting molecule called NADP forming NADPH (reduced NADP)

3) the energy given to each photosystem by the electron is used to actively transport protons (H+) from the stroma into the thykaloid to build a chemiosmotic gradient (conc gradient for protons)

4) The protons in the thykaloid are pumped through an enzyme called ATP synthase which provides energy to turn the head of the enzyme and force the reaction of ADP and Pi to form ATP

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11
Q

Calvin cycle (light independent reaction)

A

1) 5 C chain – ribulose bisphosphate (RuBP)

2) CO2 –> carbon fixation with an enzyme called rubisco (catalyses joining of CO2 and RuBP)

3) unstable 6 carbon intermediary molecule -> quickly breaks down to form 2 molecules of glycerite-3-phosphate (GP)

4) ATP from LDR to ADP

5) Reduced NADP from LDR to NADP return to LDR

6) triose phosphate x2 = glucose (some of triosephosphate is used to form sugars)

7) ATP from LDR to ADP and Pi

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12
Q

DCPIP practical

A

DCPIP (LDR):

-DCPIP competes with NADP as an additional electron acceptor. Reduces rate of LDR as there is less reduced NADP

-different concentrations of CDCPIP + plant cells (IV)

-DV = rate of photosynthesis measured by mass of sugar produced

-CV = light, CO2, temp, H2O

-higher conc of DCPIP the lower the mass of sugar produced

Limitations –> need balances w high resolution, less reliable - can measure glucose conc after using benedicts reagent and a colorimeter

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13
Q
A
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14
Q

chromatography practical

A

-used chlorophyll based substance

-use capillary tube to add a drop of solution to a pencil drawn baseline

-dip chromotography paper into a solvent below baseline

-remove before it reaches top and identify solvent front

-calculate Rf vaue = distance travelled by compound / distance travelled by solvent front

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15
Q

heat stress decreases the light-dependent reaction of photosynthesis

Explain why this leads to a decrease in the LDR

A

-there will be less ATP and less reduced NADP formed which are both needed in the LDR

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16
Q

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

A

-decreasing activity of RUBISCO reduces amount of carbon fixation of CO2 and RuBP to for intemediary 6 carbon unstable molecule therefore reducing amount of GP made

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17
Q

where is rubisco found in a cell

A

stroma

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18
Q

what part of the chloroplast does LDR occur

A

thykaloid membrane

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19
Q

define the term photolysis

A

splitting of water using light

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20
Q

why is photolysis also known as photoionisation

A

-loss of an electron in the prescence of light

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21
Q

equation for photolysis

A

H2O –> 2H+ + 2e- + 1/2O2

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22
Q

site of LDR

A

thykaloid mebrane

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23
Q

light energy in LDR is converted to

A

ATP and NADPH

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24
Q

photolysis of water is important form

A

generating an electrochemical gradient

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25
Q

describe how oxygen is produced during the light-dependent reactions of photosynthesis

A

-oxygen is produced via the photolysis of water (splitting of water using light)

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26
Q

ATP is synthesised from ADP and Pi during the LDR. Describe the structures in a chloroplast that are involved in the reaction

A

-H+ ions pumped from the stroma and through thykaloid membrane
-thylakoid membrane contains protons that acts as electron carriers (electron transport chain)
-ATP synthase

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27
Q

explain how a herbicide which reduces the transfer of electrons reduces the rate of photosynthesis in weeds

A

-less energy re;eased as less electrons move down electron transport chain
-less H+ ions pumped out of thylakoid membrane and through ATP synthase
-fewer H+ ions = weaker electrochemical gradient
-less energy to phosphorylate the production of ATP by ADP and Pi
-less H+ ions to reduce NADP

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28
Q

electron transport chain establishes

A

chemiosmotic gradient
an electrochemical gradient for the active transport of H+ ions

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29
Q

describe what happens during the light dependent reaction (5)

A

-chlorophyll absorbs light energy
-electrons are exicted and exit the chloroplasts
-electron transport chain releases energy to pump H+ ions from stroma and through thylakoid membrane
-energy used to join ADP and Pi into ATP
-photolysis of water (write equation)
-NADP reduced by electrons into NADPH

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30
Q

stage 1 of light dependent reaction

A

a photon of light hits a molecule of chlorophyll in photosystem II. The chlorophyll molecule becomes excited and loses an electron, becoming oxidised. This is called photoionisation. The electron is transferred to the primary pigment molecule via a series of REDOX reactions

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31
Q

stage 2 of LDR

A

-Stage 2 = the organisation of the chlorophyll molecules means that energy becomes focused on the primary pigment reaction centre. This releases a high energy electron which then enters the electron transport chain

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32
Q

stage 3 of LDR

A

the lost electron must be replaced in order for the process to continue. To provide the electrons a molecule of water needs to be split.

H2O –> 2H+ + 2e- + ½O2

This only happens in the presence of light (photoionisation)

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33
Q

stage 4 of LDR

A

the electron lost from photosystem II passes down the electron transport chain via a series of REDOX reactions, with each reaction energy is lost. This energy is used to pump H+ ions from the stroma into the thylakoid space. This begins the process of chemiosmosis

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34
Q

stage 5 of LDR

A

at the same time that the chlorophyll molecules in photosystem II is being excited, the chlorophyll molecule in photosystem I is also excited. This means that it also loses an electron. This electron along with H+ ions from the photolysis of water, bind with NADP to form reduced NADP/ NADPH. The electron lost form te photosystem I is replaced by the electron lost from photosystem II

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35
Q

chemiosmotic theory

A

-the concentration of H+ ions in the thylakoid space increases

-the H+ ions then diffuse down a proton gradient via ATP synthase. The movement of H+ ions catalyses the formation of ATP

-ADP + Pi –> ATP

-this is known as photophosphorylation (addition of a phosphate molecule using light)

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36
Q

products of light dependent reaction

A

ATP
NADPH
oxygen

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37
Q

photosystem

A

Photosystem = protein containing lots of chlorophyll pigment molecules

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38
Q

electron transport chain

A

provides energy for chemiosmosis = series of proteins embedded into the membrane along which electrons can pass

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39
Q

reduced NADP

A

NADP gains H+ (from water) and e- (from chlorophyll) to be reduces

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40
Q

stage 1 of calvin cycle (light independent reaction)

A

1) CO2 is fixed by combining with a 5 carbon compound (RuBP) ribulose biphosphate. This is catalysed by the enzyme RuBISCO

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41
Q

stage 2 of calvin cycle

A

2) The 6-C compound produced is unstable so quickly breaks down into two 3-C compounds of glycerate-3-phosphate (GP)

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42
Q

stage 3 of calvin cycle

A

3) The GP is then reduced using energy from the breakdown of ATP and an electron from reduced NADP to form triose phosphates

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43
Q

stage 4 of calvin cycle

A

4) 80% of molecules of TP made are converted back into RuBP. The TP molecules re-arrange themselves to form 5-C compounds and are then phosphorylated to form RuBP

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44
Q

stage 5 of calvin cycle

A

5) 20% of the molecules of TP are used to create a 6-C compound known as glycose by binding with another molecule of TP. This can be isomerised into fructose and converted into another range of organic molecules

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45
Q

chemicals needed for LDR

A

NADP, ADP, Pi and water

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46
Q

describe what happens during photoionisation in the LDR

A

-chlorophyll absorbs light energy which causes electrons to be lost as they are exicted and move out the chlorophyll

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47
Q

explain why the studen marked the origin using a pencil rather than ink

A

ink and leaf pigments would mix

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48
Q

describe the method the student used to separate the pigments are the solution

A

-level of solvent below origin line
-remove before reaches the top end

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49
Q

suggest and explain the advantage of having different coloured pigments in leaves

A

absorbs more wavelengths for photosynthesis

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50
Q

explain how atrazine reduces the rate of photosynthesis in weeds

A

-reduced chemiosmotic gradient
-less ATP and NADP produced
-LDR slows

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51
Q

explain what would happen to the pH of the solution during this investigation

A

-pH would increase
-CO2 removed for photosynthesis

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52
Q

suggest why the rate of photosynthesis was low between these wavelengths of light

A

-less absropton
-light required for LDR

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53
Q

why does iron deficency result in a decrease in uptake of CO2

A

-less TP converted to RuBP
-CO2 combines with RuBP

54
Q

how does temperature affect enzyme activity

A

low temperatures = low kinetic energy = less chance of collisions = less E-S complexes

high temp = enzyme denature = ionic bonds break in tertiary structure = active site changes shape = no longer complimentary

55
Q

glucose + nitrates =

A

amino acids

56
Q

photosynthesis limiting factors

A

CO2
H2O
light intensity
temperature

57
Q

how does disruption in an electron transport chain reduce growth

A

less energy for chemiosmosis = less ATP and NADPH produced = less GP reduced to TP = less glucose synthesised = less other organic compounds such as amino acids

58
Q

why do low CO2 levels affect the LDR

A

Less CO2 is fixed to RuBP = less GP reduced to TP = less NADPH oxidised = less NADP to accept electrons in electron transport chain of LDR = LDR slows

59
Q

reduced TP production in iron-deficient plants

A

if electron transport is reduced then there is a lower chemiosmotic gradient to pump H+ ions through ATP synthase to produce ATP from Pi = less ATP and less NADP by electrons = less energy and electrons to reduced GP to TP

60
Q

what is the site of photosynthesis in a plant

A

leaf

61
Q

ATP production

A

ATP production in both photosynthesis and respiration is formed when protons travel down an electrochemical gradient through molecules of ATP synthase

62
Q

adaptations of the leaf

A

-large surface area
-thin
-transparent cuticle and epidermis
-long narrow packed mesophyll cells
-stomata that respond to changes in light intensity

63
Q

stroma + thylakoid

A

-H+ ions are pumped from the stroma using protein carriers in the thykaloid membrane

-photolysis of water increases H+ ion concentration in the thykaloid space and low concentration in the stroma

64
Q

adaptations of chlorophyll in the light dependent reaction

A

-thylakoid membrane provides large surface area for attachment of chlorophyll/electrons
-proteins in the granumn hold in place for maximum absorption
-selectivley permeable = establish protein gradient
-contain DNA + ribosomes

65
Q

dehydrogenase

A

Dehydrogenase​​ is an ​enzyme ​​found in plant chloroplasts that is crucial to the ​light dependent stage​​ of photosynthesis. In the light dependent stage, ​electrons ​​are accepted by ​NADP. ​​ Dehydrogenase ​catalyses​​ this reaction.

66
Q

carbon numbers in light independent reaction

A

RuBP = 5 C
GP = 3
TP = 3
Glucose = 6

67
Q

explain why the light independent reaction slows down at low temperatures

A

-light indepednent reaction involves enzymes
-enzymes denature = less kinetic energy = less collision

68
Q

how much triose phosphate is converted to RuBP

A

83%

69
Q

which process is the source of ATP used in the conversion of GP to triose phosphate

A

light dependent reaction / photophosphorylsation

70
Q

why were all tubes placed at the same distance from the lamp

A

so all tubes recieve the same amount of heat

71
Q

describe the part played by chlorophyll in photosynthesis

A

-absorbs light energy
-excites electrons
-form ATP

72
Q

explain how a lack of light caused the amount of radioactively labelled glycerate 3 phosphate to rise

A

-ATP and reduced NADP not formed
-less GP to form RuBP

73
Q

true or false -> ATP synthase is a transport protein not an enzyme

A

false -> ATP synthase is an enzyme and catalyses the formation of ATP from ADP + Pi

74
Q

active transport in LDR

A

There is a higher concentration of protons in the thylakoid space compared to the stroma. To maintain this proton gradient, there is active transport of protons from the stroma into the thylakoid space.

75
Q

oxidation vs reduction

A

oxidation = loss of H+ ions

reduction = gain of H+ ions

76
Q

no electron transport chain =

A

protons cant be actively transported into thylakoid space = no proton gradient in stroma = no ATP

77
Q

differences between glycerate-3 phosphate and TP

A

glycerate = negative O while TP has a H so needs to be reduced by NADPH to gain the hydrogen

78
Q

adaptions of chloroplast

A

-large surface area = many thylakoid
-chlorophyll pigment allows maximum absoroption of light energy
-grana surrounds stroma which allows products to move to the stroma from LDR
-chloroplast has ribosomes to make enzymes for photosynthesis
-contains accessory pigments to absorb different wavelengths of light
-thylakoid has small internal volume which maximises H+ conc

79
Q

what happens when GP is converted to TP

A

GP is reduced
-NADPH is oxidised into NADP
-ATP is hydrolysed into ADP + Pi

80
Q

how many cycles of the calvin cycle are needed to form 1 glucose molecule

A

6

81
Q

true or false -> ATP is needed to convert RuBP to GP

A

true

82
Q

dark =

A

stomata close
CO2 not used/no uptake
not used in photosynthesis

some CO2 uptake through upper surface

83
Q

explain why GP remained constant

A

-GP being used and reformed at same rate
-GP reduced to TP

84
Q

factors affecting photosynthesis

A

-CO2
-temperature
-pH
-water supply
-light intensity / wavelength / duration

85
Q

CO2

A

Low CO2 affects the Calvin Cycle. If CO2 levels are low, rubisco cannot convert RuBP to GP in step one of the Calvin Cycle. This leads to accumulation of RuBP and an overall slowing of the Calvin Cycle, which results in a fall in the production of TP/GALP.
High CO2 can cause stomata to close. However, if CO2 rises too high, then some stomata begin to close, which can lead to less CO2 uptake by the plant.
The ideal CO2 concentration is 0.4%. The atmospheric CO2 concentration is 0.04%. Increasing this by ten times to 0.4% will increase the rate of photosynthesis

86
Q

water

A

Water is needed for photolysis in the light-dependent stage. Low levels of water prevent efficient photolysis occurring during the light dependent reactions. This will disrupt production of ATP and reduced NADP, both of which are needed for the Calvin Cycle.
Water vapour and soil are sources of water. Plants can obtain water through their stomata from water vapour in the air, and also by absorbing water from soil via their roots.

87
Q

light intensity

A

Light is needed for the light-dependent stage. Light energy is needed to excite the electrons and for photolysis of water in the light-dependent stage. Without light, there would be little ATP and reduced NADP produced for the Calvin Cycle.
Certain wavelengths of light are absorbed. Light is absorbed by the photosynthetic pigments (e.g. chlorophyll a), as we learnt before. Green light is not absorbed but is instead reflected.

88
Q

role of dehydrogenase

A

catalyses the reduction of NADP to NADPH at end of the electron transport chain

89
Q

role of DCPIP

A

An electron acceptor that can accept electrons at the end of the electron transport chain to prevent NADP from being reduced to NADPH.

blue to colourless when reduced

90
Q

purpose of control experiments

A

To ensure we can see if the independent variable is the only factor affecting the investigation. In order to make comparisons.

91
Q

purpose of ice

A

Cold reduced the enzyme activity which prevents to hydrolysis of organelles.

92
Q

why did the student set up tube 1

A

to show light doesnt affect DCPIP
show reaction cant occur without chloroplasts

93
Q

explain the advantage of using IC50 in the investigation

A

to compare different chemicals

94
Q

explain how chemicals which inhibiti the decolourisation of DCPIP could slow the growth of weeds

A

-reduces energy in electron transport chain
-DCPIP accepts less electrons
-less ATP produced
-less NADPH produced
-less GP reduced to TP

95
Q

the teacher said we could not draw definite conclusions = why

A

no error bars to show if overlap occurs
-cannot determine significance

96
Q

weeds have been shown to give off small amounts of heat - why

A

energy released from electrons excited from chlorophyll molecules

97
Q

why did the relative amounts of GP and RuBP remain the same

A

-temperature = limitng factor below optimum
-light intensity = limiting factor

98
Q

purpose of the 3 leaf treatments

A

1) compare = see if open stomata reduces CO2 uptake
2) stops CO2 uptake
3) CO2 uptake cannot occur at all

99
Q

advantage of light being off

A

prevents water loss by transpiration
maintains water potential gradient in cells

100
Q

why does CO2 uptake close to zero when light is off

A

stomata close in dark
no diffusion gradient for CO2 into the leaf

101
Q

order of electron carriers

A

Y X W Z

102
Q

explain why low rate of photosynthesis between 525 and 575nm of light

A

-pigments reflected - > less absorbed
-light required for photolysis
-represents green pigment

103
Q

why did the conc of radioactive RuBP increases

A

no CO2 to combined with RuBP

104
Q

Describe how ATP is resynthesised in cells

A

-ATP synthase catalyses the condensation reaction between ADP + Pi to form ATP
-during respiration
-elimination of water molecule

105
Q

2 ways in which the hydrolysis of ATP is used in cells

A

1) phosphorylates other reactions making them more reactive
2) active transport

106
Q

why is ATP used over glucose as an energy store

A

-ATP is more manageable as it releases less energy

-ATP cannot leave the cell it was made in whilst glucose can

-ATP requires less energy to be broken down

-ATP doesnt take up storage space

ATP –> ADP + Pi (hydrolysis) (release 30.6 KJmol-1)

107
Q

uses of ATP

A

-Phosphorlyation = make more reactive

-biosynthesis (protein synthesis)

-cell division (mitosis)

-cell signalling (hormones)

-thermoregulation

-cell mobility (flagellum)

-active transport of substances across a membrane

108
Q

process of respiration

A

glycolysis –> link reaction –> krebs cycle –> oxidative phosphorylation

109
Q

where does glycolysis occur

A

-glycolysis takes place in the cytoplasm while the rest takes places in the mitochondria

-glucose = too large to fit into mitochondria

-glycolysis (anaerobic process)

-oxidative phosphorylation (Aerobic = more energy)

110
Q

products of glycolysis

A

Products –> 2 ATP molecules, x2 NADH, x2 pyruvate

111
Q

energy investment + energy harvesting phase (glycolysis)

A

Energy investment phase –> stable 6 Carbon glucose molecule is phosphorylated by 2 molecules of ATP form glucose phosphate.

Energy harvesting phase –> 6 carbon glucose phosphate is broken down into 2 molecules of TP (3 carbon molecules with Pi). Oxidation occurs where NAD is reduced to NADH involving the loss of x2 ATP molecules. This forms 2 molecules of pyruvate (stable 3 carbon molecule)

112
Q

steps of glycolysis

A

1) Glucose is phosphorylated using ATP

2) The phosphorylated glucose molecule quickly breaks down into 2 molecules of TP

3) TP is oxidised into pyruvate releasing ATP and reducing NAD into NADH

3) Net products –> x2 pyruvate, x2 ATP, x2 NADH

113
Q

The link reaction

A

-to enter the krebs cycle pyruvate needs to be converted into Acetyl CoA (a coenzyme)

-1) Decarboxylation of pyruvate to form CO2 biproduct (loss of CO2)

2) Pyruvate is oxidised resulting in the dehydrogenation of NAD to NADH + H+ (loss of hydrogen)

3) This forms acetate (2 carbon molecule)

4) This coenzyme A attaches to acetate to form acetyl CoA

114
Q

acetate

A

Acetate = x2 carbon molecule added to a co-enzyme to form acetyl CoA

115
Q

function of coenzyme A

A

Function of Co-enzyme A = transport remaining acetyl to the krebs cycle

116
Q

products of link reaction

A

Products of link reaction –> x2 acetyl CoA, x2 CO2, x2 NADH

117
Q

other than carbon compounds what other products are produced during the krebs cycle

A

ATP
NADH
FADH2

118
Q

aerobic vs anaerobic respiration

A

aerobic = requires oxygen –> produces ATP, CO2 and water

anaerobic –> takes place in the absence of oxygen + produces lactate in animals or ethanol + CO2 in yeast cells.

Both produce a little ATP

119
Q

summary of glycolysis

A

-activation of glucose by phosphorylation
-splitting of phosphorylated glucose into 2 TP
-TP is oxidised
-production of ATP

120
Q

true or false –> enzyme for glycolysis are only found in the cytoplasm

A

true

121
Q

coenzymes in photosynthesis and respiration

A

NAD + FAD = respiration
NADP = photosynthesis

NAD works with the dehydrogenase enzyme to catalyse the removal of hydrogen

122
Q

importance of the krebs cycle

A

-breaks down macromolecules into smaller ones
-produces hydrogen atoms
-regenerates 4c molecule to bind with acetylCoA
-involved in the manufacture of other compounds

123
Q

mitochondria in muscle cells

A
124
Q

importance of oxygen in respiration

A

-act as final acceptor for hydrogen atoms

125
Q

Krebs cycle

A

-Purpose of the krebs cycle is to reduce electron carriers to carry electrons and hydrogen in the electron transport chain to make ATP

-takes place in the mitochondrial matrix

126
Q

Net products of krebs cycle for 1 molecule of glucose

A

-Net products –> x2 ATP, x2 CoA, x2 FADH2, x6 NADH, x4 CO2 (must occurs twice for 1 glucose molecule bc 2 pyruvate)

127
Q

ATP + substrate level phosphorylation

A

-substrate level phosphorylation –> direct formation of ATP by transferring a phosphate group from a high energy compound (4C) to an ADP molecule

-In both respiration and photosynthesis, ATP production occurs when protons diffuse down an electrochemical gradient through molecules of the enzyme ATP synthase, embedded in the membranes of cellular organelles.

128
Q

aerobic vs anaerobic

A

-If respiration is only anaerobic, pyruvate can be converted to ethanol or lactate using reduced NAD. The oxidised NAD produced in this way can be used in further glycolysis.

If respiration is aerobic, pyruvate from glycolysis enters the mitochondrial matrix by active transport

129
Q

steps for krebs cycle

A

1) Acetyl CoA (2C) binds to 4C molecule to form Citrate (6C)

2) 6 carbon molecule is decarboxylated and oxidsed to form 5C molecule ketogluterate. NAD is reduced to NADH

3) 5 carbon molecule is oxidsed back into 4 carbon molecule (oxaloacetate). 2 molecules of NAD are reduced to NADH. FAD is reduced to FADH2. ADP + Pi participate in substrate level phosphorylation to form ATP, CO2 is produced during decarboxylation of 5 carbon molecule

4) This cycle must occur twice for 1 glucose molecule as 2 pyruvate are formed at the end of glycolysis and the purpose of the krebs cycle is to produce reduced electron carriers for the electron transport chain

5) Net products

130
Q

oxidative phosohpurlation

A

Reduced NAD and FAD release hydrogen atoms. Reduced NAD and reduced FAD from the previous steps release hydrogen atoms in the mitochondrial matrix, and in the process they become NAD and FAD again

Hydrogen atoms break up into protons and electrons. The hydrogen atoms split up into both H+ ions and electrons. The H+ stay in the matrix.

The electrons enter the electron transport chain (ETC). The electrons are taken up by the electron carriers in the ETC. The electrons move along the ETC, from carrier to carrier, and at each carrier the electrons release energy.

The energy from electrons is used to pump protons. The released energy at each carrier is used by the electron carriers to pump H+ from the mitochondrial matrix into the intermembrane space. This forms an electrochemical gradient – there is a higher H+ concentration in the inter-membrane space than in the matrix.

Protons diffuse down the gradient. Protons diffuse from the inter-membrane space to the matrix, down the electrochemical gradient. This movement of protons is chemiosmosis.

ATP synthase transports the protons. Protons are unable to diffuse through the phospholipid bilayer, so instead go through the enzyme ATP synthase. Proton movement provides potential energy, which rotates a section of ATP synthase, and causes phosphorylation of ADP (ADP + Pi → ATP).

Water is formed. The electrons leave the last electron carrier and pass into the matrix, where and are accepted by oxygen. H+ also joins, forming water – a product of respiration.

131
Q

chemiosmosis + oxidative phosphorylation

A

Chemiosmosis = movement of ions across a membrane bound structure down an electrochemical gradient. Movement of H+ ions to produce ATP.

-oxidative phosphorylation is the last stage of respiration and takes place in the inner mitochondrial membrane (cristae)

Aqa a level biology (6 decks)

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