Question 1

A patient develops a sore throat and fever two days after exposure to Streptococcus pyogenes. The infection resolves within a week. Which classification best describes this infectious disease?

Accepted Answer

It is an acute disease.

Question 2

Which of the following best distinguishes a sign from a symptom in infectious diseases?

Accepted Answer

A sign is an objective change observed by others, while a symptom is a subjective experience reported by the patient.

Question 3

During the 2014 Ebola outbreak in West Africa, the disease spread rapidly across several countries and continents. Which term best describes this pattern of disease occurrence?

Accepted Answer

Pandemic

Question 4

Which of the following is the correct sequence of stages in the development of an infectious disease?

Accepted Answer

Incubation period → Prodromal period → Period of illness → Period of decline → Period of convalescence

Question 5

A housefly lands on feces and then on a sandwich, transferring bacteria in the process. What mode of transmission is this?

Accepted Answer

Mechanical vector transmission

Question 6

Which of the following is a virulence factor that helps bacteria evade phagocytosis?

Accepted Answer

Presence of a capsule

Question 7

Which of the following is a physical factor of innate immunity that helps prevent microbial entry?

Accepted Answer

Mucous membranes lining the respiratory tract

Question 8

What is the primary role of inflammation in the innate immune response?

Accepted Answer

To localize and eliminate injurious agents and remove damaged tissue

Question 9

Fever is a common response to infection. Which of the following best describes its beneficial effect?

Accepted Answer

Fever enhances the activity of immune cells and inhibits some microbial growth.

Question 10

Activation of the complement system can result in several outcomes. Which of the following is NOT a direct result of complement activation?

Accepted Answer

Increased antibody production

Question 11

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

Accepted Answer

Humoral immunity is mediated by antibodies produced by B cells, while cellular immunity is mediated by T cells.

Question 12

Which immunoglobulin is primarily responsible for the secondary immune response and is the most abundant in serum?

Accepted Answer

IgG

Question 13

Which of the following best describes the function of MHC class II molecules?

Accepted Answer

They present exogenous antigens to helper T cells.

Question 14

Clonal selection is a critical process in adaptive immunity. What is its main purpose?

Accepted Answer

To select and expand lymphocytes that recognize a specific antigen.

Question 15

A child receives a vaccine containing inactivated virus. Which type of immunity is being induced?

Accepted Answer

Artificially acquired active immunity

Question 16

Which of the following best explains why a person who recovers from measles is usually protected from reinfection for life?

Accepted Answer

Immunological memory allows for a rapid and effective secondary response.

Question 17

A newborn receives antibodies from its mother through breast milk. Which type of immunity does this represent?

Accepted Answer

Naturally acquired passive immunity

Question 18

A patient is bitten by a rabid animal and receives an injection of rabies immunoglobulin. Which type of immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 19

A person with a genetic deficiency in complement protein C3 is more susceptible to bacterial infections. Which of the following best explains why?

Accepted Answer

C3 is central to all complement activation pathways and is required for opsonization and formation of the membrane attack complex.

Question 20

A patient with HIV has a low CD4+ T cell count. Which aspect of their immune response is most directly impaired?

Accepted Answer

Cellular immunity mediated by helper T cells

Microbiology Study Notes: Infectious Diseases and Immunity (Chapters 14–16)

Study Guide - Practice Questions

Study Guide - Flashcards