5.2.5 - Light-independent reactions

Question 1

What Can The LIR Be Referred To As?

Answer 1

Calvin cycle.

Question 2

What Complex Organic Molecules Does The LIR Produce & What Are They Used For?
(3 Points)

Answer 2

~ Starch -> Storage.

~ Sucrose -> Transport.

~ Cellulose -> Making cell walls.

Question 3

What Does The LIR Require From The LDR Instead Of Light?
(2 Points)

Answer 3

~ ATP.

~ Reduced NADP.

Question 4

What Is RuBP?
(2 Points)

Answer 4

~ Ribulose bisphosphate.

~ 5 carbon compound (5C).

Question 5

What Is GP?
(2 Points)

Answer 5

~ Glycerate 3-phosphate.

~ 3 carbon compound (3C).

Question 6

What Is GALP?
(2 Points)

Answer 6

~ Glyceraldehyde 3-phosphate.

~ 3 carbon compound (3C).

Question 7

What Are The 3 Main Steps Involved In The LIR Reaction?

Answer 7

1) Carbon dioxide is combined with RuBP, producing 2 molecules of GP.

2) GP is reduced to GALP, in a reaction involving reduced NADP and ATP.

3) RuBP is regenerated from GALP in reactions that use ATP.

Question 8

What Are The Steps Involved In The Catalysation Of CO2 & RuBP?
(3 Points)

Answer 8

~ CO2 combines with RuBP in a reaction catalysed by the enzyme RUBISCO.

~ The resulting 6C compound becomes unstable and splits in two.

~ This results in two molecules of GP.

Question 9

What Are The Steps Involved In The Reduction Of GP?
(3 Points)

Answer 9

~ Energy from ATP and hydrogen from reduced NADP, are used to reduce the two molecules of GP to two 3C molecules known as GALP.

~ Some of the carbons in GALP go towards the production of useful organic molecules such as glucose, while the rest remain in the Calvin cycle to allow the regeneration of RuBP.

~ 2 molecules of GALP contain 6 carbon atoms, 5 of which are needed to regenerate RuBP.