CAIE A Level Biology 9700 · Inheritance
In plants, the hormone gibberellin promotes stem elongation by causing the breakdown of DELLA repressor proteins. In bacteria, the lac operon controls the production of enzymes needed to metabolise lactose. Outline the mechanisms by which gibberellin activates gene expression and how this differs from the control of the lac operon in E. coli.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
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