Calvin Cycle

Question 1

Calvin Cycle

Answer 1

Also known as Dark Reaction, or Light-Independent Reaction –> occurs in stroma

Question 2

Process - Carbon Fixation

Answer 2

1. 3 CO2 molecules captured by 3 RuBP (each 5-C) and 3 H2O removed -catalyzed by enzyme rubisco, to produce 3 6-C molecules
2. Unstable, so quickly break down into 6 3-C molecules called PGA

Question 3

Process - Reduction Reactions

Answer 3

3. 6 PGA phosphorylated by 6 ATP (producing 6 ADP)
4. Then reduced by 6 NADPH (producing 6 NADP+), and 6 Pi removed, creating 6 G3P

Question 4

G3P

Answer 4

5. 1 G3P removed from cycle to make glucose; however 2 G3P = 1 glucose, so two cycles are needed
   - G3P can also make proteins, fats, or pyruvate for CR

Question 5

Process - RuBP Regeneration

Answer 5

6. Rest of 5 G3P undergo variety of reactions called “sugar shuffle” to reform 3 RuBP:
   - Addition of 2 H2O
   - Removal of 2 Pi
   - Phosphorylation by 3 ATP (producing 3 ADP)