The light-independent reaction

Question 1

What products from the light-dependent reaction are used to reduce CO2 in the light-independent reaction?

Answer 1

ATP and NADP

Question 2

Why is the light-independent reaction affected by the light-dependent reaction even though it doesn’t require light?

Answer 2

The light-independent reaction is reliant on the products of the light-dependent reaction

Question 3

Where does the light-independent reaction take place?

Answer 3

The stroma of the chloroplasts

Question 4

What is this stage often referred to as?

Answer 4

The Calvin cycle

Question 5

What is the first stage of the calvin cycle?

Answer 5

CO2 from the atmosphere diffuses into the leaves via the stomata and dissolves in the water around the walls of the mesophyll cells which then diffuses through the plasma membrane, cytoplasm and chloroplast membranes into the stroma

Question 6

When the CO2 enters the stroma, what does it combine with and how?

Answer 6

CO2 combines with the 5-carbon compound ribulose biphosphate (RuBP) using an enzyme (Rubisco)

Question 7

What does the combination of CO2 and RuBP produce?

Answer 7

2 molecules of the 3-carbon compound, glycerate-3-phosphate (GP)

Question 8

How are the ATP and reduced NADP from the light-dependent reaction used in the Calvin cycle?

Answer 8

They are used to reduce the activated GP to triose phosphate (TP)

Question 9

What happens to the NADP once it is used to reduce the activated GP in the 4th stage of the Calvin cycle?

Answer 9

It re-forms and goes back to the light-dependent reaction to be reduced again by accepting more hydrogen

Question 10

What are some of the triose phosphate molecules converted into?

Answer 10

Useful organic substances, such as glucose

Question 11

What are most of the triose phosphate molecules used for?

Answer 11

Regenerating ribulose biphosphate using ATP from the light-dependent reaction