Regulation of Gene Expression

The tryptophan operon is a repressible operon that is

• turned off whenever tryptophan is added to the growth medium

• turned on only when glucose is present in the growth medium.

When this is taken up by the cell, it binds to the repressor so that the repressor no longer binds to the operator:

• inducer

• repressor

Transcription of the structural genes in an inducible operon

• occurs continuously in the cell.

• starts when the pathwayʹs substrate is present.

Muscle cells and nerve cells in one species of animal owe their differences in structure to

• having different genes.

• having different genes expressed.

Tags

NGSS.HS-LS3-2

If you were to observe the activity of methylated DNA, you would expect it to

• be unwinding in preparation for protein synthesis.

• have turned off or slowed down the process of transcription.

Which enzyme was used to produce the molecule in the Figure?

• ligase

• a restriction enzyme

Which of the following occur during RNA processing? (more than 1 answer applies)

• exons can be removed

• spliceosomes remove introns

• a poly-A tail and GTP cap are added

• DNA helicase unzips DNA

• activator sequences initiate transcription

Which of the following is a mechanism of gene expression regulation in eukaryotic cells?

• DNA methylation

• RNA splicing

• Protein folding

• Lipid synthesis

In the lac operon, what is the role of the lac repressor?

• To activate transcription

• To inhibit transcription

• To enhance translation

• To degrade mRNA

What is the function of an enhancer in gene expression?

• To increase the rate of transcription

• To decrease the rate of transcription

• To terminate transcription

• To initiate translation