Question 1

Which of the following best describes the role of the promoter region in a gene?

Accepted Answer

It is the DNA sequence where RNA polymerase binds to initiate transcription.

Question 2

A nonsense mutation occurs in the coding region of a gene. What is the most likely consequence for the protein product?

Accepted Answer

The protein will be truncated and likely nonfunctional due to an early stop codon.

Question 3

Which of the following sequences represents a possible transcription start site?

Accepted Answer

A region where RNA polymerase binds and begins synthesizing RNA.

Question 4

If a mutation deletes an enhancer sequence upstream of a gene, what is the most likely effect?

Accepted Answer

Transcription of the gene will decrease or be abolished.

Question 5

Given the mRNA sequence $$5'\ UCA\ AAA\ UAA\ 3'$$ for WRN (wildtype), which codon represents the translation stop site?

Accepted Answer

$$UAA$$

Question 6

A missense mutation changes the codon $$AAA to$$ $$AAU in $$the WRN gene. What is the most likely result?

Accepted Answer

A single amino acid will be changed, possibly affecting protein function.

Question 7

Which of the following best explains why different cell types (e.g., muscle vs. eye cells) express different genes?

Accepted Answer

They have different sets of transcription factors and control elements active.

Question 8

In the genetic code table, which codon is a stop codon?

Accepted Answer

$$UAA$$

Question 9

A reporter gene experiment shows decreased mRNA levels when a control element is mutated. What does this suggest about the control element?

Accepted Answer

It is likely an enhancer required for transcription activation.

Question 10

Which of the following is the correct order of events in gene expression from DNA to protein?

Accepted Answer

Transcription → Translation → Protein folding

Question 11

If the template DNA strand is $$3'\ TAT\ CGG\ AAG\ GGG\ CCG\ 5'$$, what is the corresponding mRNA sequence?

Accepted Answer

$$5'\ AUA\ GCC\ UUC\ CCC\ GGC\ 3'$$

Question 12

Which of the following is a function of RNA polymerase during transcription?

Accepted Answer

It synthesizes RNA from a DNA template.

Question 13

A mutation changes the codon $$GGG to$$ $$AGG in a $$gene. Using the genetic code, what type of mutation is this?

Accepted Answer

Missense mutation

Question 14

Which of the following best describes the function of an enhancer region?

Accepted Answer

It increases the rate of transcription by binding activators.

Question 15

If a cell lacks a specific transcription factor required for a gene's enhancer, what is the expected outcome?

Accepted Answer

The gene will not be transcribed efficiently.

Question 16

Which of the following is true about the direction of transcription?

Accepted Answer

RNA is synthesized in the $$5' \rightarrow 3'$$ direction.

Question 17

A mutation in the WRN gene results in the mRNA sequence $$5'\ UGA\ AAA\ UAA\ 3'. $$What is the effect of the $$UGA$$ codon at the beginning?

Accepted Answer

It acts as a stop codon, terminating translation prematurely.

Question 18

Which of the following best explains the difference in gene expression between two alleles with mutations in the enhancer region?

Accepted Answer

The allele with the intact enhancer will produce more mRNA than the mutated allele.

Question 19

Which of the following is NOT a possible consequence of a mutation in the coding region of a gene?

Accepted Answer

Change in the rate of DNA replication

Gene Structure, Regulation, and Mutations: Study Notes

Study Guide - Practice Questions