Question 1

Which of the following best explains why RNA-dependent RNA polymerase (RDRP) is an ideal target for antiviral drugs?

Accepted Answer

RDRP is only found in viral genomes and not in human cells, reducing the risk of harming the patient.

Question 2

A patient is prescribed tetracycline for a bacterial infection. Which of the following is the most likely side effect, and what is the underlying mechanism?

Accepted Answer

Brown discoloration of teeth due to binding to calcium in developing teeth

Question 3

A sample of ocean water is diluted in a 1:10 series. 0.1 mL of the second dilution is plated, and 191 colonies are counted after incubation. What is the original concentration of bacteria in the sample?

Accepted Answer

$$191,000$$ cfu/mL

Question 4

Which of the following best describes the function of the viral envelope?

Accepted Answer

It mimics the host cell membrane, allowing the virus to evade the immune system.

Question 5

Which of the following antibiotics targets the 50s subunit of bacterial ribosomes and may cause heart arrhythmia as a side effect?

Accepted Answer

Azithromycin

Question 6

A patient develops severe anemia after being treated with penicillin. Which type of hypersensitivity reaction is most likely responsible, and what is the mechanism?

Accepted Answer

Type II; IgG antibodies bind to penicillin-coated red blood cells, activating complement and causing cell lysis

Question 7

Which of the following statements about the adaptive immune system is correct?

Accepted Answer

It is more effective than the innate immune system and has memory, allowing for a rapid response upon second exposure.

Question 8

Which of the following best explains why antibiotics that inhibit bacterial ribosomes can also cause mitochondrial toxicity in humans?

Accepted Answer

Mitochondria in human cells evolved from prokaryotic ancestors and have ribosomes similar to bacterial ribosomes.

Question 9

Which of the following is the correct sequence of events in the lytic viral replication cycle?

Accepted Answer

Attachment, uncoating, assembly, lysis

Question 10

A patient with a history of multiple antibiotic allergies is prescribed a sulfa drug. Which of the following is a serious potential side effect of this medication?

Accepted Answer

Stevens-Johnson Syndrome

Question 11

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies bind to pathogens, enhancing their phagocytosis by macrophages.

Question 12

Which antibody is primarily responsible for agglutination and complement activation, and what is its structure?

Accepted Answer

IgM; pentamer

Question 13

A newborn develops severe anemia during a second pregnancy where the mother is Rh- and the baby is Rh+. What is the immunological basis for this condition?

Accepted Answer

Maternal IgG antibodies cross the placenta and attack fetal red blood cells.

Question 14

Which of the following best explains why red blood cell infections are particularly dangerous?

Accepted Answer

Red blood cells lack MHC I and cannot present antigens to the immune system.

Question 15

Which of the following is a unique feature of Type IV hypersensitivity reactions compared to Types I, II, and III?

Accepted Answer

They are mediated by cytotoxic T cells and macrophages rather than antibodies.

Question 16

Which of the following best describes the role of Helper T cells (CD4 cells) in the immune response?

Accepted Answer

They activate both B cells and cytotoxic T cells by recognizing antigens presented on MHC II.

Question 17

A patient is exposed to poison ivy and develops a rash 48 hours later. Which immune cells are primarily responsible for this reaction, and what type of hypersensitivity is this?

Accepted Answer

Cytotoxic T cells and macrophages; Type IV hypersensitivity

Question 18

Which of the following best explains why B-lactam antibiotics are only effective against Gram-positive bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that is targeted by B-lactams.

Question 19

Which of the following is the correct calculation for the number of colony-forming units per milliliter (cfu/mL) in a plate count assay, given the following: 1 mL of a 1:10,000 dilution is plated and 54 colonies are counted?

Accepted Answer

$$54 	imes 1,000 = 54,000$$ cfu/mL

Question 20

Which of the following best describes the function of the constant region of an antibody?

Accepted Answer

It determines the class of the antibody (e.g., IgG, IgM).

Comprehensive Study Notes: Viruses, Antimicrobial Drugs, Immunology, and Hypersensitivity

Study Guide - Practice Questions

Study Guide - Flashcards