photosynthesis Flashcards
photosynthesis I photosynthesis II
1
Q
plants and other photosynthetic pigments contain cellular organelles called what
A
chloroplasts
2
Q
what is the basic role of chloroplasts and what is this process called
A
they trap light energy from the sun and convert it to chemical energy that is stored in sugar and other organic molecules. this is photosynthesis
3
Q
what are the 2 modes that an organism uses to acquire the organic compounds it uses for energy
A
autotrophic nutrition and heterotrophic nutrition
4
Q
what are autotrophs
A
self feeders - they sustain themselves without eating anything derived from other living beings
they produce their own organic molecules from CO2 and other inorganic raw materials from the environment
5
Q
what is the ultimate source of organic compounds for nonautotrophic organisms
A
autotrophs
6
Q
what are the producers of the biosphere
A
autotrophs
7
Q
almost all ……. are autotrophs
A
plants - the only nutrients they require are water and minerals from soil, and CO2 from the air
8
Q
what are photoautotrophs
A
organisms that use light as a source of energy to synthesise organic substances - plants are photoautotrophs
9
Q
in what organisms does photosynthesis occur
A
plants, algae, some unicellular eukaryotes and some prokaryotes
10
Q
what are heterotrophs
A
they obtain organic material by the second major mode of nutrition
they are unable to make their own food and they live on compounds produced by other organisms
11
Q
how can heterotrophs obtain energy from other organisms
A
they can be decomposers - by decomposing and feeding on organic litter, such as dead organisms, faeces and fallen leaves
12
Q
dive some examples of heterotrophs
A
humans
most fungi
many prokaryotes
13
Q
what are most heterotrophs dependent on
A
photoautotrophs - that’s where they get their food from
14
Q
how were fossil fuels formed
A
from the remains of organisms that died hundreds if millions of years ago
fossil fuels represent the stores of the suns energy from the distant past
15
Q
how are plants being used in renewable fuel research
A
researchers are looking into ways of capitalizing photosynthesis to provide alternative fuels e.g. biodiesel
16
Q
what are the 2 stages of photosynthesis
A
light reactions - capture solar energy and transform it into chemical energy
calvin cycle - uses the chemical energy produced in the light reactions to make organic molecules of food
17
Q
where is photosynthesis likely to have originated from
A
a group of bacteria that had infolded regions of the plasma membrane containing photosynthetic enzymes and other molecules that functioned similarly to the membranes of the chloroplast
18
Q
according to the endosymbiont theory where did the chloroplast originate from
A
the original chloroplast was a photosynthetic prokaryote that lived inside an ancestor of eukaryotic cells
19
Q
what parts of the plant contain chloroplasts
A
all green parts of the plant including green stems and unripened fruit
20
Q
what part of the plant is the major site of photosynthesis
A
the leaves
21
Q
chloroplast are found mainly in the cells of the ………….
A
mesophyll
22
Q
what is the mesophyll
A
the tissue in the interior of the leaf
23
Q
what are the stomata
A
microscopic pores through which carbon dioxide enters the leaf and oxygen exits
24
Q
how is water absorbed by the roots delivered to the leaves
A
via veins
25
what do leaves use veins for
to receive water from the roots
| export sugar to the roots and other nonphotosynthetic parts of the plant
26
how many chloroplasts does a typical mesophyll contain
30-40
27
how many membranes does the chloroplast have
2
28
what is the fluid called on the cellular side of the membranes of the chloroplast
stroma
29
what is the membrane system called that is suspended in the stroma of chloroplasts
the thylakoid membranes
30
the thylakoid membranes separate the stroma from what in the thylakoid sacs
the thylakoid space
31
what are thylakoid sacs stacked in columns called
grana
32
what is chlorophyll and where is it found
the green pigment that gives plats their green colour and resides in the thylakoid membranes of the chloroplasts
33
where is the intermembrane space of the chloroplast
found between the outer membrane and the inner membrane
34
what drives the synthesis of organic compounds in the chloroplast
the light energy absorbed by chlorophyll
35
what is the equation of photosynthesis
6CO2 + 6H2O + light energy --> C6H12O6 + 6O2
36
what is the reverse process of photosynthesis
cellular respiration
37
what is the oxygen given off by plants derived from
water - NOT carbon dioxide
38
what does the chloroplast split water into
hydrogen and oxygen
39
what is used by some bacteria for photosynthesis instead of water and what is the by-product
hydrogen sulphide - globules of sulfur are formed as a waste product
40
how did scientist work out that water was split
they carried out 2 experiments
1. they marked the oxygen in water - this marked oxygen was found in the oxygen released from the plant
2. they marked the oxygen in carbon dioxide - this marked oxygen was found in the sugar produced and the water produced but not in the released oxygen
from this it is evident that the oxygen produced in photosynthesis comes from the splitting of water
41
where does the hydrogen from the splitting of water go
it is used to make the sugar and the water produced
42
photosynthesis and cellular respiration both involve what type of reaction
redox reactions
43
electrons increase/decrease potential energy when they move from water to the sugar in photosynthesis
increase - so the process requires energy - it is endergonic - the energy boost is provided by light
44
give an overview of the light reactions
1. water is split providing a source of electrons and protons and giving off oxygen as a by-product
2. light absorbed by chlorophyll drives the transfer of electrons and protons to an electron acceptor called NADP+ where they are temporarily stored
3. the NADP+ becomes reduced to NADPH by adding a pair of electrons along with a hydrogen ion
4. the light reactions generate ATP by using chemiosmosis to power the addition of a phosphate group to ADP (photophosphorylation)
5. the light energy has now been transferred to the chemical energy in NADPH and ATP
45
do the light reactions produce any sugar
no - this happens in the calvin cycle
46
give an overview of the calvin cycle
1. carbon dioxide is incorporated from the air into organic molecules already resent in the chloroplast (carbon fixation)
2. the carbon cycle reduces the fixed carbon to carbohydrate by the addition of electrons
3. the reducing power is provided by NADPH which acquired its electrons from the light reactions
47
is energy required to convert carbon dioxide to carbohydrate in the calvin cycle
yes it requires chemical energy in the form of ATP which is generated in the light reactions
48
what are the metabolism steps of the calvin cycle sometimes referred to as
the dark reactions or light independent reactions because none of the steps require light directly
49
why does the calvin cycle usually occur during the day of it doesn't require light
because it requires the products of the light reactions (ATP and NADPH) which can only occur in the light
50
where in the chloroplasts do the light reactions occur
the thylakoid membranes
51
where does the calvin cycle happen in the chloroplast
in the stroma
52
what is the chemical energy in NADP and ATP used for
their chemical energy is used to synthesise glucose and other molecules that can be used as energy sources
53
light is a form of energy known as what
electrochemical energy which is also called electromagnetic radiation
54
what is the distance between the crests of electromagnetic waves called
wavelength
55
what is the entire range of radiation known as
the electromagnetic spectrum
56
at what point in the electromagnetic spectrum is visible light
between 380-750nm
57
why is visible light given its name
because it can be detected as various colours by the human eye
58
what are photons
packages of light - each one has a fixed quantity of energy
59
the shorter the wavelength of light the smaller/larger the energy per photon
larger
60
which photons have more energy - those of violet light or those of red light
violet light - about twice as much energy as red
61
what part of the electromagnetic spectrum drives photosynthesis
visible light
62
when light meets matter what are the 3 things that can happen to it
it can be reflected, transmitted or absorbed
63
what are substances that absorb light known as
pigments
64
if a pigment absorbs green light is that the colour it appears
no - the colour we see is the colour that is transmitted or reflected
65
if a pigment absorbs all light what colour does it appear
black
66
if a substance absorbs no light what colour does it appear
white
67
what colour of light does chlorophyll absorb
absorbs: violet-blue and red light
| transmits and reflects: green light
68
what can the ability of a pigment to absorb light be measured by
the use of a spectrophotometer
69
what is an absorption spectrum
a graph plotting the wavelength of light against absorbance by a substance
70
what are the 2 accessory pigments in chloroplasts
chlorophyll b and the carotenoids
71
what is the key light capturing pigment in chloroplasts
chlorophyll a
72
what is an action spectrum
a spectrum that profiles the relative effectiveness of different wavelengths of radiation in driving the process
e.g. you could use photosynthesis rate as a measure of effectiveness
73
why do chlorophyll a and b absorb light at different wavelengths
they have a small structural difference
| chlorophyll a has a CH3 group whereas chlorophyll b has a CHO group
74
what colour is chlorophyll a
blue-green
75
what colour is chlorophyll b
olive green
76
what are carotenoids
hydrocarbons that are various shades of yellow and orange because they absorb violet and blue-green light
77
what is the structure of chlorophyll
its made of a porphyrin ring (light absorbing head) and a hydrocarbon tail (interacts with hydrophobic regions of proteins inside the thylakoid membranes)
78
how do some carotenoids provide photoprotection
the compounds absorb and dissipate excessive light energy that would otherwise damage chlorophyll or interact with oxygen, forming reactive oxidative molecules that are dangerous to the cell
79
what vegetable is rich in carotenoids and how does this affect your eyes
carrots - they have a photoprotective role in the human eye
80
what is the difference between plant and human antioxidants
plants produce all the antioxidants they need whereas humans need to consume some of them in their diets
81
what happens when isolated chlorophyll absorbs light
when a molecule absorbs a photon of light, one of its electrons is elevated to an orbital where it has more potential energy - this is the excited state of the pigment
the only photons absorbed are the ones whose energy is exactly equal to the energy difference between the ground state and the excited state
the excited state of the pigment is unstable and the electrons drop back down to ground state releasing their energy as heat and/or light
as the light/heat is released the chlorophyll fluoresces
82
what is a photosystem
a photosystem is composed of a reaction centre complex surrounded by several light harvesting complexes
the organisation of chlorophyll molecules along with other small organic molecules an proteins in a complex in the thylakoid membranes
83
what is the reaction centre complex of a photosystem
an organised association of proteins holding a special pair of chlorophyll a molecules and a primary electron acceptor
84
what is the light harvesting complex of a photosystem
they consist of various pigment molecules bound to proteins
85
why can photosystems harvest light over a larger portion of the electromagnetic spectrum compared to a single pigment molecule
the number and variety of pigment molecules in a light harvesting complex allows a photosystem to absorb more light
86
when a pigment absorbs a photon where is the energy passed
it is transferred from pigment molecule to pigment molecule within a light harvesting complex until it is passed to the pair of chlorophyll a molecules in the reaction centre complex
87
what makes the pair of chlorophyll a molecules in the reaction centre complex "special"
molecular environment - their location and the other molecules which they are associated with
their environment enables them to use energy from light not only to boost one of their electrons to a higher energy level but also to transfer it to a different molecule - the primary electron acceptor
88
what is the primary electron acceptor
a molecule capable of accepting electrons and becoming reduced
89
what is the first step in the light reactions
the solar powered transfer of an electron from the reaction centre complex chlorophyll a pair to the primary electron acceptor
90
when the chlorophyll electron is excited to a higher energy level the …………….. captures it in a redox reaction
primary electron acceptor
91
why does isolated chlorophyll fluoresce
because there is no electron acceptor so the electrons of the excited chlorophyll drop right back down to ground state instead of being captured by an electron acceptor
92
what are the 2 types of photosystems found in the thylakoid membrane that cooperate in the light reactions of photosynthesis
photosystem II and photosystem I
| they were named in order of discovery but photosystem II functions first in the light reactions
93
what is the difference between photosystem I and II
they have characteristic reaction centre complexes
94
what is the reaction centre complex chlorophyll a of photosystem II known as and why
P680
| because this pigment is best at absorbing light of wavelength 680 nm (red part of the spectrum)
95
what is the reaction centre complex chlorophyll a of photosystem I known as and why
P700
| because this pigment is best at absorbing light of wavelength 700 nm (far-red part of the spectrum)
96
P680 and P700 are nearly identical chlorophyll a molecules but how are they different
their association with different proteins in the thylakoid membrane affects the electron distribution in the two pigments and accounts for the slight differences in their light absorbing properties
97
what is linear electron flow
when ATP and NADH energize the two photosystems. the do this by flowing electrons through the photosystems and other molecular components built into the thylakoid membrane
this occurs during the light reactions of photosynthesis
98
what are the steps of linear electron flow
1. a photon of light strikes one of the pigment molecules in a light harvesting complex of PS II, boosting one of its electrons to a higher energy level
2. as this electron falls back to tis ground state, an electron in a nearby pigment molecule is simultaneously raised to an excited state. the energy continues to be relayed to other pigment molecules until it reaches the P680 pair of chlorophyll a molecules in the PS II reaction centre complex. an electron in the pair of chlorophylls is excited to a higher energy state
3. the electron is transferred form the excited P680 to the primary electron acceptor (the P680 becomes P680+ on the loss of the electron)
4. an enzyme catalyses the splitting of a water molecule into 2 electrons, 2 H+ and an oxygen atom. the electrons are supplied one by one to the P680+ pair, each electron replacing one that was transferred to the electron acceptor. the hydrogen ions are released into the thylakoid space and the oxygen atom binds with another oxygen atom from the splitting of another molecule of water
5. each photoexcited electron passes from the primary electron acceptor of the PS II to the PS I via an electron transport chain which is made up of the electron acceptor plastoquinone (a cytochrome complex) and a protein called plastocyanin
6. as electrons floe down the electron transport chain each component carries out redox reactions, releasing free energy that is used to pump hydrogen ions into the thylakoid space, contributing to a proton gradient across the thylakoid membrane
7. the potential energy stored in the proton gradient is used to make ATP by chemiosmosis
8. meanwhile, light energy has been transferred via light harvesting complex pigments to the PS I reaction complex, exciting an electron of the P700 pair of chlorophyll a molecules
9. the photoexcited electron is then transferred to the PS I primary electron acceptor creating P700+which can now act as an electron acceptor, accepting an electron that reaches the bottom of the electron transport chain from PS II
10. photoexcited electrons are passed in redox reactions from the primary electron acceptor of PS I down a second electron transport chain through the protein ferredoxin (this doesn't create a protein gradient and so ATP isn't produced)
11. the enzyme NADP+ reductase catalyses the transfer of electrons from ferredoxin to NADP+. 2 electrons are required for its reduction to NADPH. this process also removes H+ from the stroma
12. electrons in NADPH are at a higher energy level than they are in water (where they started) so they are more readily available for the reactions of the calvin cycle
99
what is cyclic electron flow
when photoexcited electrons take an alternative path which uses PS I but not PS II - it is a shorter circuit
100
what happens in cyclic electron flow
- the electrons cycle back from ferredoxin to the cytochrome complex, then via a plastocyanin molecule to a P700 chlorophyll in the PS I reaction centre complex
- there is no reduction of NADPH and no release of oxygen from this process but cyclic flow does generate ATP
101
when does cyclic electron flow occur
in photosynthetic bacteria that only have one PS
| in photosynthetic species that possess both PSs (all eukaryotes and some prokaryotes
102
what evidence suggests that cyclic electron flow may be photoprotective
plants with mutations that render them unable to carry out cyclic electron flow are capable of growing well in low light, but not well where light is intense
103
what is chemiosmosis
the process that uses membranes to couple redox reactions too ATP production
104
how do chloroplasts and mitochondria generate energy
an electron transport chain pumps protons across a membrane as electrons are passed through a series of carriers that are progressively more electronegative
the electron transport chains transform redox energy to a proton motive force, potential energy stored in the form of a H+ gradient across a membrane
an ATP synthase complex in the same membrane couples the diffusion of hydrogen ions down their gradient to ATP synthesis
105
what is the difference in the ATP generation process in mitochondria and chloroplasts
mitochondria use chemiosmosis to transfer chemical energy from food molecules to ATP
chloroplasts use chemiosmosis to transform light energy into chemical energy in ATP
106
describe the pumping of protons in the mitochondria
electron transport proteins in the inner membrane of the mitochondria pump protons from the mitochondrial matrix out to the intermembrane space which serves as a reservoir of hydrogen ions
107
describe the pumping of protons in the chloroplast
electron transport proteins in the thylakoid membrane of the chloroplast pump protons from the stroma into the thylakoid space which serves as a reservoir of hydrogen ions
108
what 3 steps in the light reactions contribute to the hydrogen gradient across the thylakoid membrane
1. water is split by PS II on the side of the membrane facing the thylakoid space
2. a plastoquinone transfers electrons to the cytochrome complex, 4 protons are translocated across the membrane into the thylakoid space
3. a hydrogen is removed from the stroma when it is taken up by NADP+
109
how do H+ power ATP synthesis in photosynthesis
the diffusion of H+ from the thylakoid membrane to the stroma powers ATP synthase
110
on what side of the thylakoid membrane is NADPH produced
the side of the membrane facing the cytosol, where the calvin cycle reactions take place
111
how is the calvin cycle similar to the citric acid cycle
the starting material is regenerated after some molecules enter and others exit the cycle
112
is the calvin cycle catabolic or anabolic
anabolic - it synthesises carbohydrates and consumes energy
113
in what form does carbon enter the calvin cycle
as CO2
114
how does the calvin cycle use NADPH
as a reducing power for adding high energy electrons to make sugar
115
what is the carbohydrate called that is produced directly from the calvin cycle
glyceraldehyde 3 phosphate (G3P)
116
for the net synthesis of one molecule of G3P, how many times does the cycle need to take place
3 times - fixing a total of 3 molecules of CO2 (one per cycle)
117
what does carbon fixation refer to in photosynthesis
the initial incorporation of CO2 into the organic material
118
what are the 3 phases of the calvin cycle
1. carbon fixation
2. reduction (gaining electrons)
3. regeneration of the CO2 acceptor (RuBP)
119
describe phase 1 of the calvin cycle: carbon fixation
- each CO2 molecule is incorporated one at a time, by attaching it to a 5 carbon sugar RuBP. the enzyme that catalyses this is rubisco
- the product of the reaction is a 6 carbon intermediate that is short lived because it is so unstable and immediately splits in half forming 2 molecules of 3 phosphoglycerate (per CO2 molecule)
120
what is the most abundant protein in chloroplasts
rubisco
121
describe phase 2 of the calvin cycle: reduction
- each molecule of 3 phosphoglycerate receives an additional phosphate group from ATP, becoming 1,3 - bisphosphoglycerate
- a pair of electrons donated from NADPH reduces 1,3 - bisphosphoglycerate, which loses a phosphate group in the process to glyceraldehyde-3-phosphate (G3P) which stores more potential energy
122
for every 3 CO2 molecules that enter the calvin cycle how many G3P molecules are produced
6 - but only one molecule can be counted as net gain because the rest are required to complete the cycle
123
how many carbons are in 5 molecules of G3P
15
124
one molecule of G3P is used by the plant cell but what happens to the other 5
they are recycled to regenerate the 3 molecules of RuBP
125
describe phase 3 of the calvin cycle: regeneration of the CO2 acceptor (RuBP)
- in a complex series of reactions, the carbon skeletons of 5 molecules of G3P are arranged by the last steps of the calvin cycle into three molecules of RuBP
- to do this, the cycle spends 3 more molecules of ATP
the RuBP is now prepared to receive CO2 again and the cycle continues
126
how many carbons are there in 6 molecules of G3P
18 - 3 carbons in each
127
to synthesise one glucose molecule, the calvin cycle uses ……... molecules of CO2, …………. molecules ATP and …………….. molecules NADPH
6
18
12
128
to synthesise one molecule of G3P, the calvin cycle uses ……... molecules of CO2, …………. molecules ATP and …………….. molecules NADPH
3
9
6
129
what are c3 plants
plants whose initial fixation of carbon occurs via rubisco and their first product is a 3 carbon compound, 3-phosphoglycerate
130
give examples of c3 plants
rice, wheat and soybean
131
what happens to c3 plants on hot, dry days
they produce less sugar because the declining level of CO2 in the leaf starves the calvin cycle due to stomata being partially closed
132
when CO2 becomes scarce what is the response of c3 plants
- they use oxygen in place of CO2 for the calvin cycle - rubisco is able to bind to oxygen
- this process produces 2 carbon compounds
- peroxisomes and mitochondria within the cell rearrange and split this compound, producing CO2
- this is photorespiration
133
what is the difference between normal respiration and photorespiration
photorespiration uses energy instead of generating it
134
how do photorespiration and photosynthesis differ
photorespiration produces no sugar - in fact it actually decreases photosynthetic output
135
what are c4 plants
they preface the calvin cycle with an alternate mode of carbon fixation that forms a 4 carbon comound as its first product
136
what are the 2 most important photosynthetic adaptations
c4 photosynthesis
| crassulacean acid metabolism (CAM)
137
give examples of some c4 plants
sugarcane
corn
members of the grass family
138
in c4 plants what are the two distinct types of photosynthetic cells
bundle sheath cells and mesophyll cells
139
what are bundle sheath cells
they are arranged into tightly packed sheaths around the veins of the leaf
140
where are the mesophyll cells found
between the bundle sheaths and the leaf surface
141
are the bundle sheaths and mesophyll cells close together
they are closely associated and never more than 2-3 cells away from each other
142
describe the c4 pathway
1. the first step is carried out by the enzyme PEP carboxylase found in the mesophyll cells. this enzyme adds CO2 to PEP forming the 4 carbon product, oxaloacetate. PEP carboxylase has a much higher affinity for CO2 than does rubisco and no affinity for oxygen. PEP carboxylase can fix carbon when rubisco can't (when stomata are partially closed - low CO2)
2. the 4 carbon product is transported to the bundle sheath cells through plasmodesmata
3. the 4 carbon compounds release CO2, which is re-fixed into organic material by rubisco and the calvin cycle. ATP is used to convert pyruvate to PEP, which can accept addition of another CO2, allowing the reaction cycle to continue
143
how do bundle sheath cells generate ATP
by cyclic electron flow
144
why is cyclic electron flow the only mode of generating ATP by bundle sheath cells
because they only contain PS I not PS II
145
in what environments is the c4 adaptation particularly useful
in hot regions with intense sunlight - where stomata partially close during the day
146
what effect does increasing C2 concentration have on c3 and c4 plants
c3 - benefits c3 plants by lowering the level of photorespiration that occurs
c4 - largely unaffected
147
what effect does increasing temperature have on c3 and c4 plants
c3 - negative effect - would increase levels of photorespiration
c4 - largely unaffected
148
what is more efficient c3 or c4 photosynthesis
c4 - because it uses less water and resources
149
what kind of plants have the CAM adaptation
water storing plants such as pineapples and cacti
these plants open their stomata during the night and open them during the day - this helps them conserve water but also prevents CO2 from entering the leaves
150
what happens in CAM plants
when their stomata are open at night they take up CO2 and incorporate it into a variety of organic acids
this is called cam
151
what do the mesophyll cells of CAM plants store
organic acids they make during the night, in their vacuoles until morning when the stomata close
152
what happens to CAM plants during the day
light reactions supply ATP and NADPH for the calvin cycle
| CO2 is released from the organic acids made the night before to become incorporated into sugars in the chloroplasts
153
how is the CAM pathway similar to the c4 pathway
CO2 is first incorporated into the organic intermediates before it enters the calvin cycle
154
how is the c4 pathway different from the CAM pathway
in c4 the initial steps of carbon fixation are separated structurally from the carbon cycle whereas in CAM the two steps occur in the same cell but at different times
155
what proportion of the organic material made by photosynthesis is consumed as fuel for cellular respiration in plant cell mitochondria
50%
156
what can the sugar produced from photosynthesis be used to synthesise
lipids, proteins, cellulose and other products
sucrose - for in the cytosol
starch - for in the chloroplast
cellulose - for the cell wall
157
what is the main ingredient of cell walls
cellulose
158
what process is responsible for the presence of oxygen in our atmosphere
photosynthesis
159
ATP and NADPH are used too convert CO2 to what kind of phosphates
hexose (6 carbon)
160
what are phototrophs
photosynthetic organisms
161
where do the light reactions take place
the thylakoid membrane
162
where does the calvin cycle take place
the stroma
163
what reduces NADP+ to NADPH in the light dependent reactions
a hydride ion - a hydrogen with one proton and two electrons
164
the organelles inside the chloroplasts are prokaryotic/eukaryotic
prokaryotic
165
chlorophyll contains chlorin which is similar to heme but contains which ion instead of iron
magnesium 2+
166
what are the major pigments in anaerobic photosynthetic bacteria
bacteriochlorophylls a and b
167
in order to absorb light what features do pigments need to have
the molecules of the pigment must have a conjugated bonding system (alternating double bonds)
168
which pigments increase the range of absorbance of plants
carotenoids
169
where are the PS
they contain many proteins and pigments embedded in the thylakoid membrane
170
how are the two PS connected
by cytochrome complex
171
PS I are concentrated in the lamella membranes (not grana stacks) and are actively engaged in what type of electron transport
cyclic electron transport
172
electron falls downhill/uphill in energy between the two photosystems
downhill
173
light is capture by ………. complexes
antenna
174
............… drives the transport of electrons from PS II through the cytochrome complex to PS I and ferredoxin and then to NADPH
light energy
175
in order to be used in chemiosmosis what characteristic must a membrane have
it must be impermeable to hydrogen ions so that they can't just flow back through
176
what is photophosphorylation
synthesis of ATP that is fully dependent on light energy
177
what are the 2 major particles of chloroplast ATP synthase
CF0 and CF1
178
what does CF0 do
it spans the membrane and forms a pore for hydrogen ions
179
what does CF1 do
protrudes into the stroma and catalyses ATP synthesis from ADP and Pi
180
for each CO2 reduced in the calvin cycle, how many ATP and NADPH are required
2 NADPH
| 3 ATP
181
what cycle balances the ATP use in thee calvin cycle
cyclic electron transport - it produces ATP but not NADPH
182
cyclic flow increases the …………... force and increases ATP production, but no NADP+ is produced
proton motive
183
the enzymes in the reductive phase of the calvin cycle are all found in which other biological pathway
glycolysis
184
the reaction of RuBP and CO2 using the enzyme rubisco is reversible/irreversible
irreversible
185
rubisco doesn't discriminate well between which two molecules
oxygen and carbon dioxide
