Calvin Cycle

Question 1

Where do the Light-Independent Reactions (Calvin Cycle) occur?

Answer 1

In the stroma

The stroma is the fluid-filled space surrounding the thylakoids in chloroplasts.

Question 2

What is the first step of the Calvin Cycle?

Answer 2

Fixation: CO₂ + RuBP (via Rubisco) → unstable 6C → split into 3-PGA

Rubisco is the enzyme that catalyzes the fixation of carbon dioxide.

Question 3

What is produced during the Reduction phase of the Calvin Cycle?

Answer 3

G3P

ATP and NADPH are used to convert 3-PGA into G3P.

Question 4

How many G3P molecules exit the Calvin Cycle to form sugars?

Answer 4

1 G3P

This G3P can be used to synthesize glucose and other carbohydrates.

Question 5

What happens during the Regeneration phase of the Calvin Cycle?

Answer 5

5 G3P + ATP → 3 RuBP

This step regenerates RuBP to allow the cycle to continue.

Question 6

How many times must the Calvin Cycle run to produce 1 glucose molecule?

Answer 6

Twice

Each cycle produces G3P, and two G3P are needed to form one glucose.