CAIE A Level Biology 9700 · Inheritance
Describe the differences between structural genes and regulatory genes, and between repressible and inducible enzymes. Use the lac operon in E. coli to illustrate the control of protein production by an inducible enzyme system. Then describe how gibberellin activates gene expression in plant cells by causing the breakdown of DELLA protein repressors. In your answer, explain the role of transcription factors in controlling gene expression in eukaryotes.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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