AP Biology: Unit 5 Review

What are the coding segments of a stretch of eukaryotic DNA called?

• introns

• exons

Introns are significant to biological evolution because

• their presence allows exons to be shuffled.

• they protect the mRNA from degeneration.

When does translation begin in prokaryotic cells?

• as soon as transcription has begun

• once the pre-mRNA has been converted to mRNA

A frameshift mutation could result from

• a base insertion only.

• either an insertion or a deletion of a base.

• a base deletion only.

Tags

NGSS.HS-LS3-2

What does the operon model attempt to explain?

• the coordinated control of gene expression in bacteria

• the mechanism of viral attachment to a host cell

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.