AP BIOLOGY

Detailed explanation-1: -Allolac tose binds to the lac repressor and makes it change shape so it can no longer bind DNA. Allolactose is an example of an inducer, a small molecule that triggers expression of a gene or operon.

Detailed explanation-2: -High tryptophan: The tryptophan binds to the trp repressor and causes it to change shape, converting into its active (DNA-binding) form. The trp repressor with the bound tryptophan attaches to the operator, blocking RNA polymerase from binding to the promoter and preventing transcription of the operon.

Detailed explanation-3: -In molecular biology, an inducer is a molecule that regulates gene expression. An inducer functions in two ways; namely: By disabling repressors. The gene is expressed because an inducer binds to the repressor.

Detailed explanation-4: -An inducer (allolactose or an analog) binds to the repressor and prevents its binding to the operator, thereby releasing the repression and allowing transcription of the lac operon.

Detailed explanation-5: -Operons may be inducible or repressible Some operons are usually “off, ” but can be turned “on” by a small molecule. The molecule is called an inducer, and the operon is said to be inducible. For example, the lac operon is an inducible operon that encodes enzymes for metabolism of the sugar lactose.