Question 1

Which of the following best describes the structure of DNA in prokaryotes compared to eukaryotes?

Accepted Answer

Prokaryotic DNA is typically circular and located in the nucleoid, while eukaryotic DNA is linear and found in the nucleus.

Question 2

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides in the 5' to 3' direction?

Accepted Answer

DNA polymerase

Question 3

A mutation occurs when a nucleotide is replaced by another, resulting in a change in the amino acid sequence of a protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 4

Which of the following best explains why complementary base pairing is essential for DNA replication?

Accepted Answer

It ensures that each new DNA strand is identical to the original template.

Question 5

In the context of gene expression regulation, which mechanism allows bacteria to coordinate the expression of multiple genes in response to environmental changes?

Accepted Answer

Operons

Question 6

A researcher is using the Ames test to determine whether a chemical is a mutagen. Which of the following best describes the purpose of the Ames test?

Accepted Answer

To assess the ability of a chemical to induce mutations in bacterial DNA.

Question 7

Which of the following is a mechanism of horizontal gene transfer in bacteria that involves the uptake of naked DNA from the environment?

Accepted Answer

Transformation

Question 8

A virus with a single-stranded RNA genome uses its RNA as a template for both genome replication and gene expression. Which type of viral genome is this?

Accepted Answer

Positive-sense single-stranded RNA virus

Question 9

Which of the following best describes the lytic cycle of a bacteriophage?

Accepted Answer

The phage causes immediate destruction of the host cell by producing new viral particles.

Question 10

Which of the following is a reason why antibiotics are ineffective against viruses?

Accepted Answer

Viruses lack cell walls and metabolic pathways targeted by antibiotics.

Question 11

A patient is diagnosed with a persistent latent viral infection. Which of the following best describes the time course and pattern of this infection?

Accepted Answer

The virus remains dormant in host cells and can reactivate periodically.

Question 12

Which of the following best describes the composition and function of a biofilm?

Accepted Answer

A biofilm is a community of microbes embedded in a self-produced matrix, providing protection and enhanced survival.

Question 13

Which equation best represents exponential microbial growth under ideal conditions?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 14

A bacterium is classified as an obligate anaerobe. Which of the following best describes its oxygen requirement and adaptation?

Accepted Answer

It cannot tolerate oxygen and lacks enzymes to detoxify reactive oxygen species (ROS).

Question 15

Which of the following best describes the difference between sterilization and disinfection?

Accepted Answer

Sterilization removes all microbes including spores, while disinfection reduces microbial load but may not eliminate spores.

Question 16

Which of the following is a physical method of decontamination that is most effective for sterilizing heat-sensitive medical equipment?

Accepted Answer

Filtration

Question 17

Which of the following best describes the role of ATP in anabolic pathways?

Accepted Answer

ATP provides energy required for biosynthesis of macromolecules.

Question 18

During aerobic cellular respiration, how many molecules of ATP are produced from one molecule of glucose ($$C_6H_{12}O_6$) in eukaryotes?

Accepted Answer

$$32$$ ATP

Question 19

Which of the following best describes the function of the electron transport chain in cellular respiration?

Accepted Answer

It pumps protons across a membrane to generate a proton-motive force for ATP synthesis.

Question 20

A biochemical test is performed to identify a bacterial species based on its ability to ferment lactose. Which of the following best explains the physiological basis for this test?

Accepted Answer

Fermentation of lactose produces acid, which lowers the pH and changes the color of the indicator.

Microbiology Study Guide: Genetics, Viruses & Prions, Microbial Growth, and Metabolism (Chapters 5-8)

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