Question 1

Which of the following best explains why naked viruses are generally more stable in the environment compared to enveloped viruses?

Accepted Answer

Naked viruses have a protein capsid that is resistant to desiccation and disinfectants.

Question 2

A patient is infected with a retrovirus. Which enzyme is crucial for the replication of this virus, and what is its primary function?

Accepted Answer

Reverse transcriptase; it synthesizes DNA from an RNA template.

Question 3

During the lytic replication cycle of a bacteriophage, which stage immediately follows biosynthesis of viral components?

Accepted Answer

Maturation (assembly of new virions)

Question 4

Which of the following best describes the function of the complement system's classical pathway?

Accepted Answer

It is activated by antibodies and leads to the destruction of pathogens.

Question 5

A bacterial exotoxin consists of two parts: the B subunit and the A subunit. What is the primary role of the B subunit?

Accepted Answer

It binds to the host cell, facilitating entry of the A subunit.

Question 6

Which of the following is an example of an indirect mode of disease transmission?

Accepted Answer

A person contracts a disease by touching a contaminated doorknob (fomite).

Question 7

Which of the following best defines the term 'incidence' in epidemiology?

Accepted Answer

The number of new cases of a disease in a specified time frame.

Question 8

A patient is exposed to a bacterial endotoxin. Which of the following is most likely to occur as a result?

Accepted Answer

Fever and inflammation due to the release of lipopolysaccharides (LPS).

Question 9

Which of the following best describes the role of helper T cells (CD4+)?

Accepted Answer

They coordinate immune responses by activating other immune cells.

Question 10

A patient receives a subunit vaccine. Which of the following best describes this type of vaccine?

Accepted Answer

It contains only specific antigens from the pathogen, not the whole organism.

Question 11

Which of the following best explains why opportunistic pathogens can cause disease in immunocompromised individuals?

Accepted Answer

They are normally harmless but can cause disease when the host's immune defenses are weakened.

Question 12

Which of the following is a correct sequence of events in phagocytosis?

Accepted Answer

Chemotaxis $$\rightarrow$$ adherence $$\rightarrow$$ ingestion $$\rightarrow$$ digestion $$\rightarrow$$ exocytosis

Question 13

A patient is exposed to a superantigen. What is the most likely immune response?

Accepted Answer

Excessive activation of the immune system, potentially leading to toxic shock.

Question 14

Which of the following best describes the function of IgG antibodies?

Accepted Answer

They are the most abundant antibodies in serum and provide long-term immunity.

Question 15

A patient is diagnosed with a disease that is constantly present in a particular population or region. Which epidemiological term best describes this disease?

Accepted Answer

Endemic

Question 16

Which of the following best describes the mechanism of action for the ELISA (enzyme-linked immunosorbent assay) test?

Accepted Answer

It uses enzyme-linked antibodies to detect the presence of specific antigens or antibodies.

Question 17

Which of the following is a key difference between the lytic and lysogenic cycles of bacteriophage replication?

Accepted Answer

In the lysogenic cycle, viral DNA integrates into the host genome as a prophage.

Question 18

A researcher is studying the LD$$_{50} ($$lethal dose 50) of a bacterial toxin. What does this value represent?

Accepted Answer

The dose required to kill 50% of a test population.

Question 19

Which of the following is a function of regulatory T cells (Treg)?

Accepted Answer

They regulate and suppress immune responses to prevent autoimmunity.

Question 20

A patient is exposed to a pathogen and develops symptoms after a period of time. Which stage of disease development does this period represent?

Accepted Answer

Incubation period

Microbiology Study Guide: Viruses, Pathogenesis, Immunity, and Vaccines

Guida di studio - Domande di pratica

Study guide - Flashcard