Biology 9700 · AS & A Level · Gene control

Gene control — practice question

Genes play a part in controlling the overall phenotype of an organism.
(a)[5]

Using haemophilia as an example, describe how a gene, a protein and a phenotype are related.

(b)[3]

In the pea plant, Pisum sativum, the genotype lele gives plants with short stems (dwarf plants). Explain how the lele genotype and its gene product results in dwarf plants.

(c)[3]

Dwarf plants can also form when the genes controlling growth are not activated (switched on). Explain how DELLA proteins function as repressors by preventing gene expression.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: a gene codes for a protein that controls phenotype

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