Explain5 marksChallenge
In the bacterium Escherichia coli, the lac operon controls the production of enzymes needed for lactose metabolism. In plants, the hormone gibberellin stimulates seed germination by activating the expression of genes that code for hydrolytic enzymes. Explain how the lac operon and the gibberellin signalling pathway both involve regulatory proteins that control gene expression, but achieve this through different mechanisms. In your answer, refer to:
- the roles of structural and regulatory genes
- the terms inducible and repressible
- the specific regulatory molecules involved in each system.