Edexcel A-Level Biology A2 5.4 Light Independent Reactions and Calvin Cycle Products Questions

Trace carbon dioxide fixation by RUBISCO, reduction of GP using ATP and reduced NADP, GALP export and RuBP regeneration in the cycle.

Exam points

describe carbon fixation of carbon dioxide by RUBISCO to form GP
explain reduction of GP using ATP and reduced NADP to form GALP
explain GALP use in biomass formation and regeneration of RuBP

[Maximum number: 5]

Photosynthesis consists of the light-dependent reactions and the light-independent reactions.

(a)

The light-independent reactions use products of the light-dependent reactions to produce simple sugars.

[ 5 ]

(i)

Simple sugars have the formula $\mathrm{C}_{n} \mathrm{H}_{2 n} \mathrm{O}_{n}$ .

Name the inorganic molecule from which each element in a simple sugar originated.

C

H

O

[ 2 ]

An answer that includes the following points:

- C and O from carbon dioxide (1)

- H from water (1)

ACCEPT CO2

ACCEPT $\mathrm{H}_{2} \mathrm{O}$

DO NOT ACCEPT O from water

(2)

(ii)

Simple sugars are used in the synthesis of new biological molecules.

Which row of the table shows the inorganic ions that are needed to synthesise these new biological molecules?

Table for Question (ii) — Edexcel A-Level Biology A2

[ 3 ]

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Edexcel A-Level Biology A2 5.4 Light Independent Reactions and Calvin Cycle Products Questions question 1

Question (a)

Question (i)

Question (ii)