Question 1

Which of the following best describes mutualism in symbiosis?

Accepted Answer

Both organisms benefit from the relationship.

Question 2

A patient develops pneumonia after being hospitalized for a surgical procedure. Which term best describes this infection?

Accepted Answer

Nosocomial infection

Question 3

Which of the following is NOT one of Koch's postulates?

Accepted Answer

The microorganism must be resistant to all antibiotics.

Question 4

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

Accepted Answer

Period of illness

Question 5

A rabies outbreak occurs in a region where the virus is usually present at low levels. What type of disease occurrence does this represent?

Accepted Answer

Epidemic

Question 6

Which of the following virulence factors allows bacteria to evade phagocytosis by host immune cells?

Accepted Answer

Capsule

Question 7

Which equation correctly represents the calculation of attack rate in an epidemic?

Accepted Answer

$Attack\ Rate = \frac{Number\ of\ new\ cases}{Population\ at\ risk} 	imes 100$

Question 8

Which of the following best describes the difference between exotoxins and endotoxins?

Accepted Answer

Exotoxins are secreted proteins, while endotoxins are components of the outer membrane of Gram-negative bacteria.

Question 9

Which of the following is a cytopathic effect (CPE) commonly seen in viral infections?

Accepted Answer

Syncytia formation

Question 10

Which immune cell is primarily responsible for antibody production?

Accepted Answer

B cell

Question 11

Which of the following is NOT a function of the complement system?

Accepted Answer

Antibody production

Question 12

A patient is exposed to a pathogen and develops a rapid, non-specific immune response. Which type of immunity is this?

Accepted Answer

Innate immunity

Question 13

Which of the following best describes the process of opsonization?

Accepted Answer

Coating of pathogens with antibodies or complement to enhance phagocytosis

Question 14

Which equation represents the calculation of antibody titer in a serum sample?

Accepted Answer

$Antibody\ Titer = \frac{Highest\ dilution\ showing\ positive\ reaction}{1}$

Question 15

Which of the following is a mechanism by which Trypanosoma brucei evades the host immune response?

Accepted Answer

Antigenic variation

Question 16

Which of the following is a primary lymphoid organ?

Accepted Answer

Thymus

Question 17

Which of the following best describes the role of memory cells in the immune response?

Accepted Answer

They enable a faster and stronger response upon re-exposure to the same antigen.

Question 18

Which of the following is a function of interferons in host defense?

Accepted Answer

Inhibiting viral replication

Question 19

Which of the following is a characteristic of IgM antibodies?

Accepted Answer

They are the first antibody produced during a primary immune response.

Question 20

Which of the following best describes the difference between MHC class I and MHC class II molecules?

Accepted Answer

MHC class I presents endogenous antigens to CD8+ T cells, while MHC class II presents exogenous antigens to CD4+ T cells.

Learning Objectives Unit 3

Study Guide - Practice Questions