Calvin Cycle

Question 1

Calvin cycle is

Answer 1

Carbon fixation in thylakoids

Question 2

Where does the calvin cycle occur

Answer 2

stroma of thylakoids

Question 3

What does the calvin cycle require

Answer 3

ATP (energy) and NADPH (reduction potential)

From light DEPendent reactions

Question 4

What does carbon fixation do

Answer 4

Attach CO2 to energy rich 5-carbon sugar called

Ribulose 1,5-bisphosphate (RuBP)

Question 5

Rubisco

Answer 5

called Ribulose bisphosphate carboxylase/oxygenase

it is a 16 subunit enzyme

Question 6

What does (Rubisco) do

Answer 6

it breaks down Ribulose 1.5 bisphosphate (RuBP)

Question 7

What is Ribulose 1,5 bisphosphate broken down into by Rubisco

Answer 7

first an intermediate

then into 2 molecules of 3-phosphoglycerate & water

Question 8

How many turns of the calvin cycle to make 1 molecule of glucose

Answer 8

6 turns

Question 9

When 1 glucose is made from 6 turns of the calvin cycle what else is produced

Answer 9

18 ATP (total) & 12 NADPH (total)

Question 10

There are so many steps. State the 3 main steps of calvin cycle

Answer 10

1) Carbon fixation (carboxylation)
2) Reduction
3) Regeneration of RuBP

Question 11

when 3 CO2 come into the cycle what happens with carbon fixation?

Answer 11

With Rubisco it makes two 3-phosphoglycerate with one turn of calvin cycle

Question 12

What does Rubisco add CO2 to make 3-phosphoglycerate

Answer 12

Attach CO2 to RuBP (Ribulose 1.5 bisphosphate)

Question 13

3-phosphoglycerate is reduced but needs what

Answer 13

ATP & NADPH

Question 14

3-phosphoglycerate is reduced with ATP/NADPH to what

Answer 14

Glyceraldehyde-3-phosphate (G3P)

Question 15

Glyceraldehyde-3-phosphate (G3P) makes what

Answer 15

used to make glucose

2 G3P to make 1 glucose* very complicated

Question 16

What is glucose used for in plants?

Answer 16

Energy source (glycolysis)
Energy storage (starch = polysaccharide of glucose)
Structure (cell wall = polysaccharide of glucose)

Question 17

In the following simplified diagram of the Calvin cycle, which step (A to E) is catalyzed by the abundant enzyme Rubisco?

Answer 17

Rubisco catalyzes the carboxylation of ribulose 1,5-bisphosphate (a five-carbon sugar) as the first reaction in carbon fixation.
Look at 5 carbon to 3 carbon with adding CO2