Calvin Flashcards
What is the light-independent stage of photosynthesis also known as?
The Calvin cycle
Named after Melvyn Calvin, who studied its sequence of reactions.
Where do the reactions of the Calvin cycle take place?
In the stroma of the chloroplast.
Does the light-independent stage require light energy?
No, it does not require energy from light.
What are the inputs needed for the light-independent stage?
ATP and reduced NADP from the light-dependent stage.
What happens to the inputs from the light-dependent stage in darkness?
They will run out, limiting the Calvin cycle.
What five-carbon compound reacts with carbon dioxide in the Calvin cycle?
Ribulose bisphosphate (RuBP).
What enzyme catalyzes the reaction of carbon dioxide with RuBP?
Ribulose bisphosphate carboxylase, or rubisco.
What is produced when carbon dioxide reacts with RuBP?
Two molecules of glycerate-3-phosphate (GP).
What does it mean when carbon dioxide is said to be ‘fixed’?
It has been removed from the environment and incorporated into the plant cell.
Is glycerate-3-phosphate (GP) a carbohydrate?
No, GP is not a carbohydrate.
What are the final products of the reduction of GP in the Calvin cycle?
Phosphorylated three-carbon sugar, triose phosphate (TP).
What is used to reduce GP to triose phosphate (TP)?
Energy from ATP and hydrogen from reduced NADP.
Most (five-sixths) of the triose phosphates are used to
regenerate RuBP. This process requires more ATP to be
used. The rest of the triose phosphates (one-sixth) are
used to produce other molecules needed by the plant.
Some of these triose phosphates condense to become
hexose phosphates. These are used to produce starch
for storage
sucrose for translocation around the
plant
or cellulose for making cell walls. GP can be
converted to glycerol and fatty acids to produce lipids
for cellular membranes. Plants can also produce all 20
of the naturally occurring amino acids that they need
