Light Independent Stage of Photosynthesis - Calvin Cycle

Where does the light-independent stage of photosynthesis occur?

In the stroma of chloroplasts

What is used within the light-independent stage of photosynthesis? (2)

The products of the light-dependent stages of photosynthesis, ATP and reduced NADP

What is stage 1 of the Calvin cycle?

ribulose bisphosphate and carbon dioxide combine

Outline stage 1 of the Calvin cycle as ribulose bisphosphate and carbon dioxide combine (2)

enzyme ribulose bisphosphate carboxylase (rubisco), catalyses the uptake of carbon dioxide by ribulose bisphosphate

What is stage 2 of the Calvin cycle?

Formation of 2 3-carbon molecules

Outline stage 2 of the Calvin cycle as the formation of 2 3-carbon molecules

The unstable 6-carbon compound formed from the combination of carbon dioxide and ribulose bisphosphate immediately splits into 2 molecules of glycerate-3-phosphate

What is stage 3 of the Calvin cycle?

reduction of glycerate-3-phosphate

Outline stage 3 of the Calvin cycle as the reduction of glycerate-3-phosphate (3)

reduced NADP and ATP from the light-dependent stages of photosynthesis are used to reduced the 2 glycerate-3-phosphate molecules to 2 triose phosphate molecules, this is the first carbohydrate made, NADP is reformed as it has been oxidised

What is stage 4 of the Calvin cycle?

the fate of triose phosphate

Outline stage 4 of the Calvin cycle as the fate of triose phosphate (4)

for every 6 triose phosphate molecules produced, 1 triose phosphate is converted to glucose phosphate then into starch through a condensation reaction, 5 triose phosphate molecules are used to regenerate ribulose bisphosphate, using ATP from the light-dependent stages of photosynthesis

What are the products that can be synthesised from the triose phosphate molecules produced? (5)

glucose, sucrose, fatty acids, glycerol, amino acids

How is sucrose produced?

2 glucose molecules combining in a condensation reaction

How are fatty acids produced?

acetyl CoA can be synthesised from triose phosphate then converted to fatty acids

How are amino acids produced?

with the addition of nitrogen obtained from nitrates