Chapter 14 Testbank Questions

How many promoters are in an operon?

1

A deletion in an operon removes the promoter. How will that affect the transcript that is produced from the operon?

The transcript will not be produced

The regulation of the CAP complex using cAMP is an example of inducible genetic regulation.

true

Allosteric regulation is accomplished by

a small molecule that fits into a site on the enzyme that is not the active site

An enzyme catalyzes a substrate into a final product. When the concentration of the final product is high enough, it binds to a regulatory site on the enzyme. This binding at the regulatory site changes the shape of the enzyme, which prevents it from binding the substrate and prevents formation of more final product. This is an example of a(n) ________.

allosteric enzyme

Antisense RNA does which of the following?

binds to the mRNA and prevents translation

A riboswitch only affects translation of an operon.

false

DNA that contains instructions for two or more structural genes produces monocistronic mRNA.

false

In the lac operon, the operator site is recognized by an activator protein.

false

Negative transcriptional regulation is conducted by activator proteins.

false

Operons that code for anabolic enzyme systems are typically regulated by inducers.

false

Operons that code for catabolic enzyme systems are typically regulated by repressors.

false

Enzymes involved in metabolism are most likely regulated via ________.

feedback inhibition

If a bacteria is placed in an environment that contains both glucose and lactose, the regulation of the lac operon will allow which nutrient to be processed first?

glucose

For these questions, match the following to its appropriate letter. Use each letter only once. inducible repressible co-repressor inducer

inducible- lac operon repressible- Trp operon co-repressor- Tryptophan inducer- allolactose

Translational regulatory proteins recognize specific areas of what molecule?

mRNA

Which of the following is an example of post translational regulation in prokaryotes?

phosphorylation of an enzyme

An activator is present and results in the increase in transcription of the target gene. This is an example of ________.

positive control

A deletion in an operon removes the terminator. How will that affect the transcript that is produced from the operon?

the transcript will be produced, but longer than normal

If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario.

transcription would be difficult to activate in the absence of glucose

Constitutive genes are those that have constant levels of expression.

true

Repressor proteins are responsible for negative transcriptional regulation.

true

The form of regulation that involves a physical change in the shape of an enzyme is called allosteric regulation.

true

A mutation in the lacI gene prevents the gene product from binding allolactose. What will the expression level of the operon be in the absence of lactose?

no transcription

Regulation of gene expression may occur at which of the following levels? Check all that apply.

post translation translation transcription

The regulation of protein function is called ________.

posttranslational regulation

In the lac operon, the CAP site is located next to the ________. When both lactose and glucose are present, this leads to a rate of transcription that is ________.

promoter, low

A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?

repressor + inducer