AP Biology Unit 6 Gene Expression

Which would you expect of a eukaryotic cell lacking telomerase?

• a reduction in chromosome length

• production of Okazaki fragments

When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

• methylation and phosphorylation of histone tails

• nucleotide excision and reconstruction

The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except

• a gene from an organism could theoretically be expressed by any other organism.

• all organisms have a common ancestor.

• DNA was the first genetic material.

• the same codons in different organisms usually translate into the same amino acids.

Tags

NGSS.HS-LS4-1

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.

A mutation in which of the following parts of a gene is likely to be most damaging to a cell?

• intron

• exon

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-2

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

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.

Tags

NGSS.HS-LS1-3

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.