Question 1

Which of the following best describes the semi-conservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 2

A mutation changes a codon from $$	ext{UUA} to$$ $$	ext{UUG}$$, both of which code for leucine. What concept does this illustrate?

Accepted Answer

Wobble hypothesis

Question 3

Which enzyme is responsible for synthesizing the RNA primer during DNA replication in prokaryotes?

Accepted Answer

Primase

Question 4

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

Accepted Answer

Nucleotide excision repair

Question 5

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 6

In the lac operon, what is the role of the repressor protein in the absence of lactose?

Accepted Answer

It binds to the operator and blocks RNA polymerase from transcribing the operon.

Question 7

Which of the following best explains why antibiotics that target peptidoglycan synthesis are ineffective against viruses?

Accepted Answer

Viruses lack peptidoglycan and do not have cell walls.

Question 8

A patient is diagnosed with a persistent chronic viral infection. Which of the following best describes this type of infection?

Accepted Answer

The virus remains in the host for long periods, producing low levels of virus without causing immediate cell death.

Question 9

Which of the following best describes the function of ribozymes?

Accepted Answer

They are RNA molecules that catalyze specific biochemical reactions.

Question 10

During aerobic respiration in prokaryotes, where does the electron transport chain occur?

Accepted Answer

In the plasma membrane

Question 11

A bacterial cell is found to be resistant to a certain antibiotic due to the acquisition of a plasmid from another cell. Which horizontal gene transfer mechanism most likely occurred?

Accepted Answer

Conjugation

Question 12

Which of the following is a key difference between lytic and lysogenic cycles in bacteriophages?

Accepted Answer

Lysogenic cycle involves integration of viral DNA into the host genome, while lytic does not.

Question 13

Which of the following best describes the function of ATP in cellular metabolism?

Accepted Answer

ATP stores and transfers energy for cellular processes.

Question 14

A microbe is classified as a chemoheterotroph. Which of the following best describes its energy and carbon sources?

Accepted Answer

Energy from chemicals, carbon from organic compounds

Question 15

Which of the following best explains why prions are medically significant?

Accepted Answer

They are misfolded proteins that can induce abnormal folding in normal proteins, leading to neurodegenerative diseases.

Question 16

Which of the following is a correct statement about substrate-level phosphorylation?

Accepted Answer

It directly transfers a phosphate group from a substrate to ADP to form ATP.

Question 17

A bacterial culture is exposed to a chemical mutagen that causes base substitutions. Which type of mutation is most likely to result if a codon for glycine ($$	ext{GGA}) is $$changed to a codon for aspartic acid ($$	ext{GAC}$$)?

Accepted Answer

Missense mutation

Question 18

Which of the following best describes quorum sensing in bacteria?

Accepted Answer

A process by which bacteria sense and respond to population density by gene regulation.

Question 19

During glycolysis, what are the net products generated from one molecule of glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$)?

Accepted Answer

$$2$$ ATP, $$2$$ NADH, $$2$$ pyruvate

Question 20

A patient is infected with a virus that has a single-stranded positive-sense RNA genome. Which of the following best describes the template used for viral protein synthesis?

Accepted Answer

The positive-sense RNA genome itself serves as mRNA for translation.

Comprehensive Study Guide: Microbial Genetics, Viruses, Growth, and Metabolism

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