Question 1

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

During transcription, which type of RNA is responsible for carrying the genetic code from DNA to the ribosome?

Accepted Answer

mRNA

Question 4

A mutation that changes a codon from $UAC$ (tyrosine) to $UAA$ (stop) is best classified as which type of mutation?

Accepted Answer

Nonsense mutation

Question 5

Which of the following statements about the lac operon is correct?

Accepted Answer

The lac operon is repressed when lactose is absent and activated when lactose is present.

Question 6

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

Accepted Answer

Conjugation

Question 7

What is the primary function of restriction enzymes in bacteria?

Accepted Answer

To cut foreign DNA at specific sequences, providing defense against viruses

Question 8

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation that inserts or deletes a base, altering the reading frame of the gene.

Question 9

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

Accepted Answer

$Phenotype = Genotype + Environment$

Question 10

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

Accepted Answer

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

Question 11

Which type of RNA is directly involved in the process of translation by bringing amino acids to the ribosome?

Accepted Answer

tRNA

Question 12

A scientist observes a bacterial strain that can grow on minimal media only when supplemented with tryptophan. What term best describes this strain?

Accepted Answer

Auxotroph

Question 13

Which of the following best explains the role of the CRISPR system in bacteria?

Accepted Answer

It provides adaptive immunity against foreign genetic elements.

Question 14

Which of the following is a direct result of a base substitution mutation?

Accepted Answer

A change in a single amino acid in the protein sequence.

Question 15

Which process is best described by the equation $DNA \rightarrow RNA \rightarrow Protein$?

Accepted Answer

Central Dogma of Molecular Biology

Question 16

Which of the following is a function of the Ames test?

Accepted Answer

To detect the mutagenic potential of chemical compounds.

Question 17

Which of the following best describes the difference between direct and indirect selection in microbial genetics?

Accepted Answer

Direct selection isolates mutants by growing them in conditions where only mutants survive, while indirect selection uses replica plating to identify mutants.

Question 18

Which of the following is NOT a characteristic of retroviruses?

Accepted Answer

They have a double-stranded DNA genome.

Question 19

Which of the following best describes the role of RNA polymerase during transcription?

Accepted Answer

RNA polymerase synthesizes RNA from a DNA template.

Question 20

A bacterial cell is exposed to UV light, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to be activated?

Accepted Answer

Excision repair

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

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