Biology 9700 · AS & A Level · Photosynthesis as an energy transfer process

Photosynthesis as an energy transfer process — practice question

This question is about photosynthesis and the factors that influence its rate in flowering plants.
(a)[2]

In flowering plants, the light-dependent reactions are performed by photosynthetic pigments, which are divided into two groups: primary pigments and accessory pigments. Outline the role played by accessory pigments in the light-dependent reactions.

(b)[4]

Photosynthetic pigments are organised into photosystems. There are two photosystems, PSI and PSII. PSI is involved in cyclic photophosphorylation, whereas PSII is not. Outline the differences between cyclic and non-cyclic photophosphorylation.

(c(i))[2]

Explain why the rate of photosynthesis levels off at $30^\circ\text{C}$.

(c(ii))[1]

On Fig. 8.1 extend the curve to show what would happen to the rate of photosynthesis if the temperature rose to $70^\circ\text{C}$.

(c(iii))[2]

Explain why you have extended the curve in this way.

(d)[4]

A palisade mesophyll cell has adaptations for photosynthesis. The table below shows some adaptations of a palisade mesophyll cell. Complete the table to show how these adaptations assist the cell in carrying out photosynthesis.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: Absorb incoming light

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