How are bacteria likely to regulate transcription of the set of genes involved in tryptophan synthesis? 1. By preventing transcription until tryptophan is absent and synthesis of tryptophan is required 2. By encoding each gene with its own promoter regulated by its own set of cis- and trans- regulatory elements 3. By stimulating constitutive expression, because tryptophan is essential 4. Not at all, because tryptophan is useless.

1. How are bacteria likely to regulate transcription of the set of genes involved in tryptophan
synthesis?
1. By preventing transcription until tryptophan is absent and synthesis of tryptophan is required
2. By encoding each gene with its own promoter regulated by its own set of cis- and trans-
regulatory elements
3. By stimulating constitutive expression, because tryptophan is essential
4. Not at all, because tryptophan is useless