photosynthesis the calvin cycle

Question 1

where?

Answer 1

stroma

Question 2

1. stage 1

Answer 2

1. CO2 enters through stomata and diffuses into stroma of chloroplast
2. combined with ribulose bisphosphate (RuBP) 5 C compound and catalysed by enzyme rubisco
3. gives unstable 6 C compound which breaks into 2 molecules of 3 C compound glycerate 3-phosphate (GP)

Question 3

2. stage 2

Answer 3

1. hydrolysis of ATP (from light dependent reaction) energy to turn 3C compound GP into different 3C compound triose phosphate (TP)
2. requires H+ ions which come from reduced NADP (recycled to NADP)
3. some TP is then converted into useful organic compounds e.g. glucose. some continues in calvin cycle to regenerate RuBP

Question 4

3. stage 3

Answer 4

5 out of every 6 molecules of TP produced in cycle are used to regenerate RuBP which uses rest of ATP from LDR

Question 5

carbohydrates

Answer 5

hexose sugars (glucose)
2 x triose phosphate joined

Question 6

lipids

Answer 6

glycerol (which is sythesies from triose phosphate and fatty acids)
fatty acids synthesised from glycerate 3-phosphate

Question 7

amino acids

Answer 7

glycerate 3-phosphate

Question 8

how many turns of the calvin cycle make one hexose sugar (e.g. glucose)

Answer 8

6

Question 9

why does it take 6 turns to make 1 hexose sugar

Answer 9

5 out of 6 TP molecules used to produce RuBp
after 3 turns only 1 TP produced to make hexose sugar
2 TP molecules needed to form 1 hexose sugar