Photosynthesis Part 3 (CR) - (Week 3)

Question 1

Where does the carbon reaction take place?

Answer 1

In the stroma (of the chloroplast)

Question 2

Which products of the LDR are required for the carbon reaction?

Answer 2

ATP & NADPH

Question 3

What are the 4 stages of the carbon reaction?

Answer 3

1. Carboxylation
2. Reduction
3. Output (of products)
4. Regeneration

Question 4

What happens in the carboxylation stage of the carbon reaction?

Answer 4

• 3 molecules of CO2 are fixed to each of the 3 rubisco
• 3x 6C molecules are made (C referring to carbon)
• They are unstable so eventually dissociate into 2x 1,3-BP molecules (6 in total)

Question 5

What is 3BP?

Answer 5

1,3-bisphosphoglycerate (3 indicates no. of carbons)

Question 6

What happens in the reduction xc

Answer 6

• ATP is used to phosphorylate the 3C molecule & is then reduced
• 6 x GP is made

Question 7

What is GP?

Answer 7

glyceraldehyde3-phosphate

Question 8

What happens in the output stage of the carbon reaction?

Answer 8

• 1 GP is used is used to form sugar (& other organic compounds e.g fatty acids & amino acids)
• The other 5 are used to produce rubisco

Question 9

What happens in the regeneration stage of the carbon reaction?

Answer 9

• Requires ATP

- Cycle can repeat