Term
| Describe Light harvesting |
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Definition
Light excites electrons
Energy passed from one
chlorophyll to the next, into the
Reaction Center
Only energy is transferred – no
electrons change hands |
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Term
| Describe the Reaction-center complex |
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Definition
◦ Accumulating energy frees a
pair of electrons from
Reaction Center chlorophylls
◦ Transferred across complex
to primary electron acceptor
Electrons replaced from H2O,
making O2 |
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Term
| What is linear electron flow? |
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Definition
A series of redox reaction pass these electrons to plastoquinone and down the electron transport chain to reaction center chlorophylls of Photosystem
or
A series of Redox reactions pass these electrons to
plastoquinone and down the electron transport chain to
reaction center chlorophylls of Photosystem I.
The process repeats itself in PSI, using accumulated light
energy to pass the electrons to Ferredoxin (the primary
electron acceptor for PSI), then to NADP+ to form NADPH
The ETC transfers protons from Stroma to Thylakoid Space
This establishes a proton gradient, then used by ATP
synthase to generate ATP |
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Term
| Know the difference between the Electron Transport Chain in Mitochondria and Chloroplast |
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Definition
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Term
| Where does the Calvin cycle occur? |
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Definition
| in the stroma of chloroplasts |
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Term
| What kind of energy does the Calvin cycle use? |
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Definition
| ATP and NADPH produced in light reactions |
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Term
| What forms during the Calvin cycle? |
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Definition
Forms glyceraldehyde-3-phosphate (G3P)
Building block for more complex sugars |
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Term
| How many calvin cycles does it take to make 1 G3P? |
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Definition
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Term
| Describe the electron transport and ATP |
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Definition
◦ The ETC transfers protons from Stroma to Thylakoid Space
◦ This establishes a proton gradient, then used by ATP
synthase to generate ATP |
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Term
| Describe the generation of ATP in the ETC |
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Definition
◦ Electron Transport Chain
establishes a proton gradient
◦ ATP synthase harvests the energy
to make ATP |
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Term
| What are the 3 phases of the Calvin cycle? |
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Definition
◦ Carbon fixation
◦ Reduction of sugar
(output)
◦ Regeneration of
electron acceptor |
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Term
| Describe carbon fixation in the calvin cycle |
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Definition
◦ Carbon fixation
CO2
is attached to Ribulose bisphosphate (RuBP) (5-C sugar)
Catalyzed by enzyme Rubisco – most abundant protein on the
planet
Resulting 6-C sugar is inherently unstable
Splits to 2 3-C sugars |
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Term
| Describe reduction of the calvin cycle |
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Definition
◦ Reduction
3-C sugars are phosphorylated from ATP
3-C sugars are reduced by NADPH
Produces 3-C sugar
1/6 leaves pathway as G3P
remaining 5/6 of G3P required to
regenerate RuBP |
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Term
| Describe regeneration of the calvin cycle |
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Definition
◦ Regeneration
5 3-C sugars rearranged to 3 5-C sugars
1 phosphate from ATP added to each 5-C sugar,
forming RuBP are formed |
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Term
| Describe what is made and what is used/needed in the calvin cycle |
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Definition
◦ 1 G3P produced for every 3 CO2
This makes sense: 3 individual
carbons enter, 1 3-C (G3P) leaves
for each cycle
Figure 10.19
3 RuBP (5-C) plus 3
CO2
(18 total C) are
needed to make 6
G3P (3-C) (18 C)
5 G3P (3-C) are
needed to make 3
RuBP (5-C) to
restart
Each cycle uses 6
NADPH and 9 ATP |
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Term
| What is the fate of G3P in the Calvin Cycle? |
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Definition
◦ Transported to cytoplasm
◦ Used to make:
Glucose
Sucrose
Etc. |
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Term
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Definition
| By how they enter the calvin cycle |
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Term
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Definition
– (rice, wheat, soybeans)
CO2
is initially fixed by Rubisco, forming
a 3-C compound in Calvin Cycle |
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Term
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Definition
(sugarcane, corn, grass)
CO2
, initially fixed by different enzyme,
forming a 4-C sugar, oxaloacetate. It is
later stripped off to enter Calvin Cycle
These reactions take place in different
cell layers: carbon fixation in mesophyll
and Calvin Cycle in Bundle-sheath cells
Pass between two via plasmosdesmata |
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Term
| Describe photosynthesis in arid conditions |
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Definition
Stomata kept closed to reduce H2O loss
O2 builds up, CO2 depleted
Photorespiration
Rubisco can substitute O2
for CO2
Produces CO2
Uses ATP, no sugar production |
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Term
| What can some C4 plants do? |
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Definition
| separate steps temporally |
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Term
| Describes the cyclic electron flow |
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Definition
◦ Ferredoxin requires NADP+ in order to make NADPH
◦ If cell is depleted of NADP+ then ferredoxin can pass electrons
back to Electron Transport Chain, making more ATP but no NADPH
Energy but no photosynthesis |
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