Gene Regulation

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

• True

• False

Prokaryotes regulate gene expression primarily

• in order to maintain homeostasis

• in response to changing environmental conditions

• during development as cells specialize

• Prokaryotes do not regulate gene expression. All genes are always on.

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

In order for a gene to be expressed, ___ must bind to the gene's ___, a specific sequence of nucleotides at one end of the gene, thus initiating transcription.

• DNA polymerase, promotor

• DNA polymerase, operator

• RNA polymerase, promotor

• RNA polymerase, operator

An operon is

• a genetic on/off switch in prokaryotes

• a genetic on/off switch in eukaryotes

• a group of related genes and the associated gene switches in prokaryotes

• a group of related genes and the associated gene switches in eukaryotes

Genes can be shut off (not expressed) when a ___ binds to the ____.

• activator, operator

• repressor, operator

• corepressor, operator

• repressor, promotor

What molecule can remove a repressor protein from the operator?

• a corepressor

• an inducer

What is the inducer in the lac operon?

• cAMP

• glucose

• lactose

• CRP

Genes can be turned on (expressed) when a(n) ____ such as CRP or cAMP receptor protein binds to the CRP binding site.

• repressor

• corepressor

• inducer

• activator

In the lac operon system, __ must first bind to CRP so that it is capable of binding to the DNA. This occurs when glucose levels are __.

• cAMP, high

• cAMP, low

• inducer, high

• inducer, low