Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are circular and found in the nucleoid, while eukaryotic chromosomes are linear and found in the nucleus.

Question 2

Which enzyme is responsible for relieving supercoiling during DNA replication in prokaryotes?

Accepted Answer

Gyrase

Question 3

A mutation changes the DNA sequence AAA to AAT. What is the effect on the mRNA and the resulting protein?

Accepted Answer

The mRNA changes from UUU to UUA, resulting in a change from phenylalanine to leucine.

Question 4

Which of the following best explains why concurrent transcription and translation can occur in prokaryotes but not in eukaryotes?

Accepted Answer

Prokaryotes lack a nuclear envelope, allowing ribosomes to access mRNA as it is being transcribed.

Question 5

Which of the following types of mutations is most likely to result in a nonfunctional protein?

Accepted Answer

Frameshift mutation

Question 6

Which of the following is a function of DNA polymerase III during DNA replication?

Accepted Answer

Adding bases to the new DNA chain and proofreading for mistakes

Question 7

A bacterium acquires resistance to an antibiotic through the uptake of a plasmid from its environment. Which process is responsible for this gene transfer?

Accepted Answer

Transformation

Question 8

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

Accepted Answer

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

Question 9

Which of the following mutagens causes frameshift mutations by inserting itself between base pairs in DNA?

Accepted Answer

Acridine dyes

Question 10

What is the result of a mutation that introduces a stop codon in the middle of a gene?

Accepted Answer

The protein will be truncated and likely nonfunctional.

Question 11

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids often carry genes for antibiotic resistance and can be transferred between bacteria.

Question 12

Which of the following best describes the process of specialized transduction?

Accepted Answer

A specific bacterial gene near the prophage is transferred by a temperate phage.

Question 13

Which of the following equations correctly represents the base pairing in DNA?

Accepted Answer

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

Question 14

Which of the following is a direct result of UV radiation on DNA?

Accepted Answer

Formation of pyrimidine dimers

Question 15

Which of the following best describes semiconservative replication?

Accepted Answer

Each new DNA molecule consists of one old and one new strand.

Question 16

Which of the following is NOT a function of ribosomal RNA (rRNA)?

Accepted Answer

Carrying genetic information from DNA to the ribosome

Question 17

Which of the following best explains why the Ames test is used in microbiology?

Accepted Answer

To screen for mutagenic and potentially carcinogenic compounds

Question 18

Which of the following is a key difference between inducible and repressible enzymes?

Accepted Answer

Inducible enzymes are synthesized only when their substrate is present, while repressible enzymes are inhibited by a signal molecule.

Question 19

Which of the following best describes the role of ligase in DNA replication?

Accepted Answer

Final binding of nicks in DNA during synthesis and repair

Question 20

Which of the following statements about gene transfer in bacteria is correct?

Accepted Answer

Horizontal gene transfer can occur via transformation, transduction, or conjugation.

Microbial Genetics: Structure, Function, and Regulation

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