Question 1

Which of the following best describes the process by which DNA polymerase synthesizes a new DNA strand during replication?

Accepted Answer

DNA polymerase adds nucleotides to the 3' end of the growing strand using the template strand for base pairing.

Question 2

Which equation correctly represents the base pairing rule for DNA synthesis?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 3

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

Accepted Answer

Nonsense mutation

Question 4

Which of the following best explains the difference between prokaryotic and eukaryotic transcription and translation?

Accepted Answer

In prokaryotes, transcription and translation occur simultaneously in the cytoplasm.

Question 5

Which of the following is NOT a component of a nucleotide?

Accepted Answer

Amino acid

Question 6

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

Helicase

Question 7

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It controls the breakdown of lactose when glucose is absent.

Question 8

A mutation changes the DNA sequence from $$5'-ATG GGC TAA-3' to$$ $$5'-ATG GGC TAAA-3'. $$What type of mutation is this?

Accepted Answer

Frameshift mutation

Question 9

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

Accepted Answer

Conjugation

Question 10

Which of the following is a characteristic of a lysogenic viral infection?

Accepted Answer

The viral genome integrates into the host DNA and can remain dormant.

Question 11

Which equation represents the relationship between genotype and phenotype in classical genetics?

Accepted Answer

$$Phenotype = Genotype + Environment$$

Question 12

Which repair mechanism is most likely to fix a thymine dimer caused by UV radiation?

Accepted Answer

Excision repair

Question 13

A patient is infected with a virus that remains dormant in nerve cells and can reactivate years later. What type of infection is this?

Accepted Answer

Latent infection

Question 14

Which of the following best describes the CRISPR system in bacteria?

Accepted Answer

An adaptive immune system that provides resistance to foreign genetic elements.

Question 15

Which of the following is true about the Ames test?

Accepted Answer

It measures the ability of a chemical to induce mutations in bacteria.

Question 16

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

Accepted Answer

The reading frame of the mRNA is altered, potentially changing all downstream amino acids.

Question 17

Which of the following best explains the role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 18

Which equation correctly represents the central dogma of molecular biology?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 19

Which of the following is a distinguishing feature of retroviruses?

Accepted Answer

They use reverse transcriptase to synthesize DNA from RNA.

Question 20

A bacterial cell is exposed to a chemical mutagen that causes the insertion of a transposon into a gene. What is the most likely outcome?

Accepted Answer

The gene will be silenced or disrupted, potentially leading to loss of function.

Microbiology Study Guide: DNA, RNA, Genetic Mutations, and Viruses

Study Guide - Practice Questions