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, so targeting it minimizes harm to the patient.

Question 2

A patient is prescribed tetracycline for a bacterial infection. Which of the following is a significant risk if this drug is given to a young child?

Accepted Answer

Permanent brown discoloration of developing teeth due to calcium binding.

Question 3

During a plate count assay, you dilute a 1 mL sample of water in a 1:10 dilution series. You plate 0.1 mL from the second dilution tube and count 191 colonies after incubation. What is the original concentration of bacteria in the sample?

Accepted Answer

$$191,000 \, \mathrm{cfu}/\mathrm{mL}$$

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

It has memory, allowing for a rapid and robust response upon second exposure to the same pathogen.

Question 7

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

Accepted Answer

Azithromycin

Question 8

A virus with a single-stranded negative-sense RNA genome must bring which enzyme with it in the capsid to initiate replication in a host cell?

Accepted Answer

RNA-dependent RNA polymerase (RDRP)

Question 9

Which of the following best explains why antibiotics that inhibit bacterial ribosomes can also cause side effects related to mitochondria in human cells?

Accepted Answer

Mitochondria in human cells have ribosomes similar to those of bacteria, so ribosomal inhibitors can disrupt mitochondrial function.

Question 10

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

Accepted Answer

IgM; pentamer

Question 11

A patient with a history of multiple strep throat infections develops nephritis. Which hypersensitivity reaction is most likely involved, and what is the mechanism?

Accepted Answer

Type III; immune complexes deposit in the nephrons, causing inflammation

Question 12

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

Accepted Answer

Attachment → Uncoating → Assembly → Lysis

Question 13

Which of the following best describes the role of Helper T cells in the immune system?

Accepted Answer

They link the innate and adaptive immune systems by activating B cells and cytotoxic T cells.

Question 14

A newborn develops severe anemia during the second pregnancy of an Rh-negative mother with an Rh-positive baby. What is the immunological basis for this condition?

Accepted Answer

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

Question 15

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

Accepted Answer

Red blood cells lack MHC I, so they cannot present antigens to the immune system.

Question 16

Which of the following is a function of the complement system in the innate immune response?

Accepted Answer

Formation of the membrane attack complex (MAC) to lyse bacterial cells

Question 17

A patient is given ciprofloxacin for a urinary tract infection. Which of the following is the mechanism of action for this drug, and what is a potential side effect?

Accepted Answer

Inhibits DNA gyrase; may cause tendon rupture and seizures

Question 18

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies or complement proteins bind to antigens, enhancing phagocytosis by macrophages.

Question 19

Which of the following statements about hypersensitivity reactions is correct?

Accepted Answer

Type I, II, and III hypersensitivity reactions are antibody-dependent, while Type IV is cell-mediated.

Question 20

Which of the following best explains why sulfa drugs such as trimethoprim do not affect human cells?

Accepted Answer

Humans do not synthesize folate and must obtain it from their diet.

Comprehensive Study Notes: Viruses, Antimicrobial Drugs, and Immunology

Study Guide - Practice Questions

Study Guide - Flashcards