Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A mutation that results in the insertion of a single nucleotide pair into a gene is most likely to cause which of the following?

Accepted Answer

A frameshift mutation

Question 3

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 4

In the lac operon of E. coli, what happens when lactose is present?

Accepted Answer

Allolactose binds to the repressor, preventing it from binding to the operator, and transcription occurs.

Question 5

Which of the following best explains why bacterial DNA replication is considered bidirectional?

Accepted Answer

Replication proceeds in two directions from a single origin of replication.

Question 6

A chemical mutagen causes adenine to pair with cytosine instead of thymine. Which mutagen is most likely responsible?

Accepted Answer

Nitrous acid

Question 7

Which of the following is a function of plasmids in bacteria?

Accepted Answer

They may carry genes for antibiotic resistance and toxin production.

Question 8

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

Accepted Answer

Transduction

Question 9

What is the role of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 10

Which of the following statements about operons is correct?

Accepted Answer

A repressible operon is usually 'on' and can be turned 'off' by a corepressor.

Question 11

A missense mutation in a gene results in which of the following?

Accepted Answer

A change in the amino acid sequence of the protein

Question 12

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codon.

Question 13

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

Accepted Answer

A bacterium acquiring a plasmid from another bacterium through conjugation.

Question 14

Which of the following is true regarding the genetic code?

Accepted Answer

There are 64 codons, but only 20 amino acids.

Question 15

Which of the following best describes the effect of methylation on gene expression?

Accepted Answer

Methylation turns genes off, but this effect can be reversed in future generations.

Question 16

A laboratory technician uses the Ames test to evaluate a chemical. What is being measured in this test?

Accepted Answer

The rate of mutation reversion in a histidine auxotroph

Question 17

Which of the following is a likely consequence if a transposon inserts itself into the middle of a gene?

Accepted Answer

The gene may be inactivated, leading to loss of function.

Question 18

Which of the following enzymes is responsible for removing RNA primers during DNA replication?

Accepted Answer

DNA polymerase

Question 19

In the context of gene regulation, what is the default state of an inducible operon?

Accepted Answer

Off

Question 20

Which of the following best explains why the presence of glucose inhibits the use of lactose in E. coli?

Accepted Answer

Glucose prevents the formation of cAMP, which is required for CAP to activate the lac operon.

Microbial Genetics: Structure, Function, and Regulation of Genetic Material

Study Guide - Practice Questions