Lecture+1 genetics

What is gene regulation?

The process of turning genes on and off, where each cell expresses only a fraction of its genes at any given time.

What is an operon?

A cluster of genes transcribed under the control of a single promoter.

Define the promoter in an operon.

A region of DNA to which RNA polymerase binds to initiate transcription.

What is the function of the operator within an operon?

It acts as an on-off switch for gene expression by binding repressor proteins.

What happens to the lac operon when lactose is present?

The genes for the enzymes that break down lactose are induced.

What does the trp operon do?

It regulates the production of tryptophan in E. coli and is repressed when tryptophan is present.

What is the role of the lac repressor?

It is a DNA-binding protein that inhibits the expression of genes involved in lactose metabolism.

What causes the lac repressor to change shape and release from the operator?

The presence of allolactose causes an allosteric change in the lac repressor.

How does CAP enhance the transcription of the lac operon?

CAP binds to a region of DNA before the lac operon promoter and helps RNA polymerase attach to the promoter.

What is attenuation in the context of the trp operon?

The process that regulates gene expression based on the levels of tryptophan available to the cell.

The __________ is a region of DNA where RNA polymerase binds to initiate transcription.

promoter

In an operon, the __________ acts as an on-off switch for gene expression.

operator

The __________ operon is involved in the metabolism of lactose.

lac

The __________ operon is responsible for regulating the production of tryptophan.

trp

When lactose is present, the lac operon genes are __________.

induced

The __________ repressor inhibits the expression of genes involved in the metabolism of lactose.

lac

The presence of __________ causes an allosteric change in the lac repressor.

allolactose

CAP enhances transcription of the lac operon by helping RNA polymerase attach to the __________.

promoter

Attenuation in the trp operon regulates gene expression based on __________ levels.

tryptophan

An operon is a cluster of genes transcribed under the control of a single __________.

promoter