Question 1

Which of the following best describes a loss-of-function allele in a gene encoding an enzyme involved in a metabolic pathway?

Accepted Answer

It results in the complete absence or reduction of enzyme activity, potentially leading to accumulation of substrate.

Question 2

A mutation in the promoter region of a gene most likely affects which aspect of gene expression?

Accepted Answer

The rate of transcription initiation by RNA polymerase.

Question 3

Which statement correctly explains why the genetic code is considered redundant but not ambiguous?

Accepted Answer

Multiple codons can specify the same amino acid, but each codon specifies only one amino acid.

Question 4

During translation in bacteria, which sequence is recognized by the ribosome to initiate protein synthesis?

Accepted Answer

The Shine-Dalgarno sequence

Question 5

Which of the following best describes the difference between DNA polymerase and RNA polymerase?

Accepted Answer

DNA polymerase requires a primer to initiate synthesis, while RNA polymerase can initiate synthesis without a primer.

Question 6

A point mutation changes a codon from $\mathrm{UAC}$ (tyrosine) to $\mathrm{UAA}$ (stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 7

Which of the following is a consequence of alternative splicing in eukaryotes?

Accepted Answer

It allows a single gene to produce multiple protein isoforms.

Question 8

Which enzyme is responsible for catalyzing the formation of peptide bonds during translation?

Accepted Answer

Peptidyl transferase

Question 9

In a laboratory experiment, a researcher uses a radioactive label to track newly synthesized mRNA. Which process is being studied?

Accepted Answer

Transcription

Question 10

Which of the following statements about the elongation phase of translation is correct?

Accepted Answer

Aminoacyl-tRNA enters the A site, peptide bond formation occurs, and the ribosome translocates along the mRNA.

Question 11

Which of the following best explains why DNA replication is not 'truly' signal-dependent?

Accepted Answer

DNA replication is regulated by cell cycle checkpoints, not by specific sequence signals.

Question 12

A mutation causes a change in chromosome structure resulting in the fusion of two chromosomes. Which type of chromosomal change is this?

Accepted Answer

Translocation

Question 13

Which of the following is true regarding the difference between transcription in bacteria and eukaryotes?

Accepted Answer

Eukaryotic transcription involves multiple types of RNA polymerase, while bacteria typically use one.

Question 14

Which of the following best describes the role of the 5' cap in eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding during translation.

Question 15

During translation, which site on the ribosome does the initiator tRNA bind to first?

Accepted Answer

P site

Question 16

Which of the following is a function of aminoacyl-tRNA synthetase?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA.

Question 17

Which process involves the removal of introns from pre-mRNA?

Accepted Answer

Splicing

Question 18

A scientist discovers a mutation that prevents the formation of the poly(A) tail on mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and have reduced translation efficiency.

Question 19

Which of the following best describes the role of release factors during translation termination?

Accepted Answer

They bind to the stop codon in the A site and promote the release of the polypeptide chain.

Gene Expression, Transcription, and Translation: Study Guide

Study Guide - Practice Questions