Question 1

Which of the following best describes the difference between a sign and a symptom of disease?

Accepted Answer

A sign is an objective indication of disease that can be measured or observed, while a symptom is a subjective experience felt by the patient.

Question 2

A patient is exposed to a pathogen but does not develop disease. Which of the following best explains why not every exposure to microbes results in disease?

Accepted Answer

The immune system and normal microbiota can prevent colonization and infection by pathogens.

Question 3

Which of the following is an example of vehicle transmission of disease?

Accepted Answer

Drinking water contaminated with Vibrio cholerae.

Question 4

Which of the following best describes the relationship in mutualism?

Accepted Answer

Both organisms benefit.

Question 5

A hospital patient develops a secondary infection after antibiotic treatment. Which concept best explains how normal microbiota protect the body from such infections?

Accepted Answer

Microbial antagonism, where normal microbiota compete with pathogens for resources and space.

Question 6

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

Accepted Answer

The microorganism must be present in healthy individuals as well as diseased individuals.

Question 7

Why do Koch’s postulates not work for all pathogens?

Accepted Answer

Some pathogens cannot be grown in pure culture, and some diseases are caused by multiple organisms or only in humans.

Question 8

Which of the following best describes the function of lysozyme in innate immunity?

Accepted Answer

It digests bacterial cell walls by breaking the $$\beta-1$$,4 glycosidic bonds in peptidoglycan.

Question 9

A newborn receives antibodies from its mother through the placenta. This is an example of:

Accepted Answer

Passive immunity

Question 10

Which antibody is primarily responsible for the first response to a new infection?

Accepted Answer

IgM

Question 11

Which of the following best describes the role of fimbriae in bacterial pathogenicity?

Accepted Answer

Fimbriae allow bacteria to adhere to host tissues, facilitating colonization.

Question 12

A patient with blood type O can safely receive blood from which of the following types?

Accepted Answer

Type O

Question 13

Which of the following is the most severe stage of disease progression?

Accepted Answer

Illness period

Question 14

Which of the following best describes the function of cytotoxic T cells?

Accepted Answer

They directly kill infected or abnormal host cells.

Question 15

Which antibody is most abundant in secretions such as saliva and breast milk?

Accepted Answer

IgA

Question 16

A laboratory technician uses an ELISA test to diagnose a patient. What is ELISA primarily used to detect?

Accepted Answer

The presence of specific antibodies or antigens in a sample.

Question 17

Which of the following best describes the process of agglutination in serology?

Accepted Answer

Antibodies bind to antigens on cells, causing them to clump together.

Question 18

Which type of hypersensitivity is associated with allergies and involves IgE antibodies?

Accepted Answer

Type I

Question 19

A child is born with hemolytic disease of the newborn. What is the underlying cause of this condition?

Accepted Answer

Maternal antibodies against fetal red blood cells cross the placenta and destroy fetal RBCs.

Question 20

Which of the following best explains why vaccines are considered the most effective way to control infectious diseases?

Accepted Answer

Vaccines stimulate the immune system to produce memory cells, providing long-term protection without causing disease.

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