Question 1

Which of the following best describes the role of Toll-like receptors (TLRs) in the innate immune response?

Accepted Answer

TLRs recognize pathogen-associated molecular patterns (PAMPs) and activate immune cell signaling.

Question 2

A patient develops a bacterial infection after recovering from influenza. This is an example of:

Accepted Answer

Secondary infection

Question 3

Which of the following statements about endotoxins is CORRECT?

Accepted Answer

Endotoxins are part of the outer membrane of Gram-negative bacteria and can cause fever.

Question 4

Which antibody class is most abundant in human serum?

Accepted Answer

IgG

Question 5

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

Accepted Answer

Adherence → Ingestion → Digestion → Exocytosis

Question 6

A newborn receives antibodies from breast milk. Which antibody class is primarily involved, and what type of immunity does this represent?

Accepted Answer

IgA; passive immunity

Question 7

Which of the following best describes the function of adhesin proteins in bacterial pathogenesis?

Accepted Answer

They enable bacteria to attach to host cell surfaces, facilitating colonization.

Question 8

Which of the following is NOT a component of the first line of defense in the human body?

Accepted Answer

Phagocytic white blood cells

Question 9

According to Koch’s postulates, which step is necessary to prove that a specific microbe causes a specific disease?

Accepted Answer

The microbe must be isolated from a diseased host and grown in pure culture.

Question 10

Which of the following best describes the difference between humoral and cellular immunity?

Accepted Answer

Humoral immunity involves antibodies produced by B cells, while cellular immunity involves T cells attacking infected cells.

Question 11

Which of the following best describes the role of interferons in the immune response?

Accepted Answer

They are signaling proteins that help protect neighboring cells from viral infection.

Question 12

Which region of the antibody molecule binds to the antigen?

Accepted Answer

Variable region

Question 13

Which of the following best describes the incubation period of a disease?

Accepted Answer

The time between exposure to a pathogen and the appearance of symptoms.

Question 14

Which of the following is a function of normal microbiota in the human body?

Accepted Answer

They compete with pathogens for nutrients and space, helping to protect the host.

Question 15

Which of the following best describes the structure of an antibody?

Accepted Answer

A Y-shaped molecule with two antigen-binding sites

Question 16

Which of the following is TRUE regarding the activation of antibody production?

Accepted Answer

Dendritic cells present antigens to T helper cells, which then activate B cells to produce antibodies.

Question 17

Which of the following best describes a vaccine?

Accepted Answer

A preparation of weakened or killed pathogens or their components that stimulates an immune response.

Question 18

Which of the following is NOT a function of white blood cells (WBCs)?

Accepted Answer

Transport of oxygen

Question 19

Which of the following best describes the difference between the variable and constant regions of an antibody?

Accepted Answer

The variable region binds to the antigen, while the constant region determines the antibody class.

Question 20

Which of the following best describes the concept of Biosafety Level (BSL) laboratories?

Accepted Answer

BSL labs are categorized from 1 to 4 based on the risk of the microbes handled and the safety precautions required.

Microbiology Study Guide: Immunity and Host-Microbe Interaction – Step-by-Step Guidance

Study Guide - Practice Questions