Biology 9700 · AS & A Level · Investigation of limiting factors

Investigation of limiting factors — practice question

Maize, Zea mays, is an important cereal food crop. In contrast with most crop plants, maize seed is formed by hybridisation between two distinct inbred parental strains.
(a(i))[3]

Explain why this is carried out.

(a(ii))[1]

Suggest one drawback of producing seed in this way.

(b(i))[3]

Suggest why photorespiration is most likely to occur in hot, dry conditions.

(b(ii))[4]

Explain how the leaf anatomy of a maize plant reduces photorespiration, even when conditions are hot and dry.

(c(i))[2]

Suggest an explanation for why changing carbon dioxide concentration had no effect on the rate of photosynthesis in the maize plants, as shown by these results.

(c(ii))[2]

Suggest one explanation for the changes in the rate of photosynthesis between 0700 hours and 1900 hours on day 1.

(i)[2]

Suggest an explanation for why changing carbon dioxide concentration had no effect on the rate of photosynthesis in the maize plants, as shown by these results.

(ii)[2]

Suggest one explanation for the changes in the rate of photosynthesis between 0700 hours and 1900 hours on day 1.

Worked solution & mark scheme

This 19-mark question has a full step-by-step worked solution and mark scheme. One marking point: hybrid vigour

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