Question 1

Which of the following best describes the process of replica plating in identifying bacterial mutants?

Accepted Answer

It involves transferring colonies from a master plate to secondary plates with different selective media to identify mutants.

Question 2

Which test is commonly used to determine if a chemical is a mutagen by measuring its ability to induce mutations in bacteria?

Accepted Answer

Ames test

Question 3

What is the main difference between conjugation and transformation in bacteria?

Accepted Answer

Conjugation requires direct cell-to-cell contact, while transformation involves uptake of free DNA from the environment.

Question 4

Which of the following is an example of horizontal gene transfer in bacteria?

Accepted Answer

Transduction by bacteriophages

Question 5

Griffith's experiment with Streptococcus pneumoniae demonstrated which of the following?

Accepted Answer

Transformation, where non-virulent bacteria became virulent by acquiring DNA from dead virulent cells

Question 6

Which enzyme is responsible for synthesizing new DNA strands during replication?

Accepted Answer

DNA polymerase

Question 7

A bacterium is exposed to UV light, resulting in the formation of thymine dimers. What type of mutation is most likely to occur?

Accepted Answer

Pyrimidine dimer formation leading to errors during DNA replication

Question 8

Which of the following best describes a missense mutation?

Accepted Answer

A single nucleotide change results in a codon that codes for a different amino acid.

Question 9

What is the primary function of the enzyme ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 10

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are small, circular DNA molecules that can carry antibiotic resistance genes.

Question 11

Which process involves the transfer of genetic material from one bacterium to another via a pilus?

Accepted Answer

Conjugation

Question 12

Which of the following is a real-world consequence of horizontal gene transfer among bacteria?

Accepted Answer

The rapid spread of antibiotic resistance in hospital settings

Question 13

Which of the following best describes the role of the Ames test in microbiology?

Accepted Answer

It detects chemicals that can cause mutations by measuring the reversion rate of mutant bacteria.

Question 14

Which of the following is an example of a frameshift mutation?

Accepted Answer

An insertion of a single nucleotide in a coding sequence

Question 15

Which of the following equations correctly represents the central dogma of molecular biology?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 16

A patient is infected with a bacterial strain that has acquired a gene for toxin production via a bacteriophage. What is this process called?

Accepted Answer

Transduction

Question 17

Which of the following best explains why bacteria can rapidly adapt to antibiotics?

Accepted Answer

They can acquire resistance genes through horizontal gene transfer mechanisms.

Question 18

Which of the following is NOT a mechanism of horizontal gene transfer in bacteria?

Accepted Answer

Binary fission

Question 19

Which of the following best describes a silent mutation?

Accepted Answer

A nucleotide change that does not alter the amino acid sequence of the protein

Question 20

Which of the following is a likely outcome if a bacterium loses the ability to perform transformation?

Accepted Answer

It will be unable to take up free DNA from the environment.

Microbiology Study Guide: Mutation, Gene Transfer, and Recombinant DNA

Study Guide - Practice Questions