Carbon Fixation
What stage of the calvin cycle is carbon fixation?
Stage 1.
How many molecules of G3P remain in the cycle?
What is 5?
The calvin cycle regenerates this molecule to ensure the cycle continues.
What is ribulose-1,5-bisphosphate (RuBP)?
This enzyme starts the Calvin Cycle by grabbing CO₂.
Who is RuBisCO?
This molecule gives electrons and hydrogen to help make sugars
What is NADPH?
Where does the cell get the additional carbon from
CO2
How many molecules of G3P make 1 glucose
2
How many additional ATP are required for this step?
What is 3?
Where does the Calvin Cycle occur?
In the stroma of a chloroplast.
How many molecules do we have at the end of carbon fixation?
6
What and how many, donate electrons to the 3-carbon intermediates?
What is 6 NADPH molecules
What happens to the remaining 5 G3P molecules
They get rearranged into 3 RuBP (5 caron molecules).
This energy molecule is needed to turn 3-PGA into G3
What is ATP?
How many carbons in one RuBP?
What is 5?
Describe why this process needs ATP
Takes 6 phosphates to 3-carbon intermediates from carbon fixation to turn into 6 G3P molecules, ADP goes back to the light reactions.
What would happen if you did not have enough ATP in this step?
G3P would not be transformed back into RuBP
What is an alternative name for the Calvin cycle?
Light independent reactions
Describe carbon fixation
3 RuBP molecules get carbon from 3 CO2, which produces a 6-carbon intermediate that then splits in half. At the end of carbon fixation, we have 6 molecules of 3-carbon intermediates.
What does the electron transfer do in this stage?
Reduces the 3-carbon intermediates to allow phosphate to bond.
This happens when RuBisCO chooses the wrong gas and wastes energy.
What is photorespiration?
Why might a student think that to make one glucose, you only need two cycles? Explain why it is 6.
3 RuBP are cycling at once, counts as 3 individual cycles, need 6 cycles therefore