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)?
What phase of photosynthesis is this?
What is 2nd?
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).
Why do we need more ATP than NADPH?
Need 9 ATP in total, only 6 NADPH, 3 additional ATP for regenreation stage
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.
Use an analogy to explain regeneration step
Up to judges
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