Chapter 14 Practice Questions

Regulation of gene expression can NOT be accomplished by controlling:

• the activity of a protein product

• the amount of mRNA that is available

• the rate of translation of mRNA

• the rate of mRNA degradation

• the rate of DNA replication

The focus of gene regulation in multicellular organisms is on:

• operons

• the specificity of products in different tissues

• economizing resources at all levels

• rapid turnover of RNA molecules

• controlling the transcription of genes involved in resource use

Bacteria rarely regulate gene products through:

• promoter sequences

• activator proteins

• repressor proeteins

• protein degradation

• operons

The researchers who first discovered the mechanism of control of a bacterial gene were:

• Hershey and Chase

• Griffith and Avery

• Watson and Crick

• Jacob and Monod

• McClintock and Morgan

The operator of the lactose operon in E. coli is located:

• between the promoter and the TATA box

• upstream of the promoter

• between the promoter and the structural genes

• among the structural genes

• anywhere on the chromosome

How does the lactose repressor block transcription of the lactose operon?

• by "turning off" the appropriate genes in the intron

• by regulating the activity of the enzymes that the operon codes for

• by binding allosterically to the appropriate genes

• by slowing the uptake of lactose into the cell

• by binding to the operator

Genes that encode proteins that are always needed are called:

• repressible genes

• promotor genes

• constitutive genes

• inducible genes

• operons

The molecular switch that controls gene expression is known as:

• the operon

• controller

• the operator

• repressor

• inducer

The inducer of the lactose operon in E. coli is:

• CAP

• AMP

• allolactose

• glucose

• galactose

Inducible genes are usually actively transcribed when:

• the molecule degraded by the enzyme(s) is present in the cell.

• repressor molecules bind to the promoter.

• lactose is absent from the cell.

• quantities of precursor materials are low.

• there is no other substrate that can be used by the cell.