Question 1

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 2

Which enzyme is responsible for removing RNA primers and replacing them with DNA nucleotides during bacterial DNA replication?

Accepted Answer

DNA polymerase I

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 4

Which of the following statements about plasmids is FALSE?

Accepted Answer

Plasmids are essential for normal metabolism and reproduction.

Question 5

In prokaryotic transcription, what is the role of the sigma factor?

Accepted Answer

It helps RNA polymerase recognize and bind to the promoter region.

Question 6

Which of the following is a key difference between prokaryotic and eukaryotic mRNA processing?

Accepted Answer

Eukaryotic mRNA undergoes capping, polyadenylation, and splicing, while prokaryotic mRNA does not.

Question 7

Which of the following best explains why UV light is mutagenic?

Accepted Answer

It causes the formation of pyrimidine dimers, which distort the DNA backbone and block replication.

Question 8

A bacterium is exposed to a chemical that slips between DNA bases, causing bulges in the DNA. What type of mutation is most likely to result?

Accepted Answer

Frameshift mutation

Question 9

Which of the following is TRUE regarding the lac operon in E. coli?

Accepted Answer

It is induced only when lactose is present and glucose is low.

Question 10

Which process involves the uptake of free DNA from the environment by a competent bacterial cell?

Accepted Answer

Transformation

Question 11

What is the function of aminoacyl tRNA synthetase in translation?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA.

Question 12

Which of the following is a direct result of a frameshift mutation?

Accepted Answer

A change in the reading frame, potentially resulting in a premature stop codon.

Question 13

Which of the following best describes the role of the operator in a prokaryotic operon?

Accepted Answer

It is a regulatory DNA sequence where a repressor protein can bind to block transcription.

Question 14

Which of the following is a function of DNA methylation in bacteria?

Accepted Answer

Protection against viral infection by distinguishing self from non-self DNA.

Question 15

A scientist uses the Ames test to screen a chemical for mutagenicity. Which result would indicate the chemical is a mutagen?

Accepted Answer

An increased number of revertant colonies on histidine-free medium.

Question 16

Which of the following is a key difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction can transfer any gene from the donor, while specialized transduction transfers only specific genes.

Question 17

Which of the following is TRUE about transposons?

Accepted Answer

They can move from one location to another within a genome, causing frameshift mutations.

Question 18

Which of the following best describes the function of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It helps position the ribosome on the mRNA for correct initiation of translation.

Question 19

Which of the following is a consequence of an error-prone DNA repair system such as the SOS response?

Accepted Answer

It introduces mutations but allows some cells to survive severe DNA damage.

Microbial Genetics: Structure, Replication, Expression, and Regulation

Study Guide - Practice Questions