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

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

Accepted Answer

Helicase

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 4

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids often carry genes that confer advantages such as antibiotic resistance.

Question 5

During DNA replication, which enzyme removes RNA primers and replaces them with DNA?

Accepted Answer

DNA polymerase I

Question 6

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

Accepted Answer

Transduction

Question 7

What is the function of the operator region in an operon?

Accepted Answer

It is the binding site for the repressor protein, controlling transcription of structural genes.

Question 8

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

Some amino acids are coded by more than one codon.

Question 9

A bacterial cell is exposed to nitrous acid, which causes adenine to pair with cytosine instead of thymine. What is the most likely result?

Accepted Answer

A base substitution (point mutation)

Question 10

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, mRNA is processed to remove introns before translation.

Question 11

Which of the following best describes the effect of catabolite repression on the lac operon?

Accepted Answer

It prevents the use of lactose when glucose is available by lowering cAMP levels.

Question 12

Which of the following is TRUE about frameshift mutations?

Accepted Answer

They shift the reading frame, potentially altering every amino acid downstream.

Question 13

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 14

A bacterium with a mutation in the gene encoding DNA gyrase would most likely have difficulty with which process?

Accepted Answer

Relaxing supercoiling ahead of the replication fork

Question 15

Which of the following best describes the process of transformation in bacteria?

Accepted Answer

Uptake of naked DNA from the environment

Question 16

Which of the following is a function of microRNAs (miRNAs) in gene regulation?

Accepted Answer

They base pair with mRNA, making it double-stranded and targeting it for enzymatic destruction.

Question 17

Which of the following is the correct sequence of events in the synthesis of the lagging strand during DNA replication?

Accepted Answer

Primase synthesizes RNA primer → DNA polymerase III synthesizes Okazaki fragments → DNA polymerase I removes RNA primer → DNA ligase joins fragments

Question 18

Which of the following best explains why mutations are important for evolution?

Accepted Answer

They create genetic diversity, which is the raw material for natural selection.

Question 19

Which of the following is a property of transposons?

Accepted Answer

They can move from one location to another within the genome.

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

Study Guide - Practice Questions