Question 1

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

Accepted Answer

Prokaryotic genomes are usually circular, lack a nucleus, and often contain plasmids.

Question 2

A bacterial cell is exposed to a mutagen that causes a substitution mutation in its DNA. Which of the following outcomes is most likely if the mutation is silent?

Accepted Answer

The amino acid sequence of the protein will remain unchanged.

Question 3

Which process allows bacteria to acquire new genetic material directly from the environment, such as DNA fragments released by dead cells?

Accepted Answer

Transformation

Question 4

In the regulation of the lac operon, what is the specific role of the repressor protein?

Accepted Answer

It binds to the operator to prevent RNA polymerase from transcribing the operon.

Question 5

Which of the following is an example of airborne transmission of a pathogen?

Accepted Answer

A person contracts tuberculosis after inhaling droplets from a cough that remain suspended in the air.

Question 6

Which stage of an infectious disease is characterized by the appearance of specific signs and symptoms?

Accepted Answer

Illness period

Question 7

A patient receives an injection of antibodies against rabies after being bitten by a rabid animal. This is an example of:

Accepted Answer

Artificially acquired passive immunity

Question 8

Which of the following best describes opsonization?

Accepted Answer

The coating of a pathogen with molecules such as complement or antibodies to enhance phagocytosis.

Question 9

Which type of symbiosis is characterized by one organism benefiting while the other is neither helped nor harmed?

Accepted Answer

Commensalism

Question 10

Which of the following cells are capable of killing virus-infected cells without prior sensitization?

Accepted Answer

Natural killer (NK) cells

Question 11

A person receives a vaccine containing inactivated toxins from a bacterium. What type of vaccine is this?

Accepted Answer

Toxoid vaccine

Question 12

Which antibody is most abundant in the blood and is responsible for long-term immunity?

Accepted Answer

IgG

Question 13

Which of the following proteins play a role in the body's defense against pathogenic microbial invasion by recognizing intracellular pathogens?

Accepted Answer

NOD proteins

Question 14

A patient is diagnosed with Chagas disease after being bitten by an insect that pierces blood vessels with its mouthparts. What type of transmission is this?

Accepted Answer

Vector-borne transmission

Question 15

Which cytokines are primarily responsible for promoting inflammation?

Accepted Answer

Tumor necrosis factor-alpha (TNF-\alpha)

Question 16

Which of the following statements about B cell receptors (BCRs) is FALSE?

Accepted Answer

BCRs are found on T cells.

Question 17

Which of the following is a multi-step process that involves both innate and adaptive immunity to eliminate infected cells?

Accepted Answer

Perforin-granzyme cytotoxic pathway by cytotoxic T cells and NK cells

Question 18

A person receives an injection with a contaminated needle. Which portal of entry does this represent?

Accepted Answer

Parenteral route

Question 19

Which of the following best describes the process of attenuation in vaccine development?

Accepted Answer

The pathogen is genetically modified to reduce its virulence so it stimulates an immune response but does not cause disease.

Question 20

Which of the following is a real-world example of naturally acquired active immunity?

Accepted Answer

A child recovers from chickenpox after being exposed to the virus.

Microbiology Exam Study Guide: Regulation, Immunity, and Disease Transmission

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