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

Photosynthesis as an energy transfer process — practice question

Fig. 7.1 presents the absorption spectra for chlorophyll a and chlorophyll b, together with the matching action spectrum.
(a(i))[2]

Explain why peak X in the action spectrum rises higher than peak Y.

(a(ii))[2]

Explain why most plants look green.

(a(iii))[2]

Chlorophyll b acts as an accessory pigment. Outline the role of accessory pigments in the light-dependent stage of photosynthesis.

(b)[5]

Describe the effects on a plant when its environmental temperature rises far above the usual range.

(c)[4]

Complete the following paragraph by selecting the most suitable words for the gaps. A chloroplast is enclosed by two phospholipid membranes. Its internal matrix, the stroma, is the location of the Calvin cycle. The stroma includes enzymes such as ................................ and also sugars, lipids and starch. A chloroplast has an internal membrane network of fluid-filled sacs called ................................, which can be arranged in stacks to make grana. The membranes of the grana contain photosynthetic pigments so that the light-dependent stage of photosynthesis can occur. The stroma contains circular ................................ which codes for some of the chloroplast proteins made by its own small ................................

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: Greater amounts of light are absorbed by chlorophyll

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