Prokaryotic Gene Regulation

All the genes in both a prokaryotic cell and a eukaryotic cell are expressed at the same time.

• True

• False

One way to regulate the expression of a gene is to control the formation of mRNA. This is called ___ control.

• transcriptional

• translational

• post-transcriptional

• post-translational

Operons are found in the cells of which of the following types of organisms?

• prokaryotes

• eukaryotes

• animals only

• viruses

A protein that binds to the operator and blocks the RNA polymerase

• regulator
• repressor
• activator
• corepressor

In the lac operon model, the genes within the operon will be expressed if:

• lactose is absent in the cell

• glucose is present in the cell

• lactose is present in the cell

What is the role of operons in prokaryote gene expression?

• It keeps the prokaryote's genes turned on

• It enable the coordinated regulation of gene activity in response to the needs of the cells

• To make proteins based on the genes' sequences

• To turn the gene on and off

What is the name of the stretch of DNA where RNA polymerase binds?

• operator

• promoter

• enhancer

• regulatory gene

A key advantage of grouping genes with related functions is that a single "on-off" switch can control the whole cluster.

• True

• False

An operon consists of all the the following EXCEPT

• operator
• promoter
• regulatory gene
• genes of the operon

The purpose of the trp operon is to produce enzymes that

• synthesize lactose

• digest lactose

• synthesize tryptophan

• digest tryptophan