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 side effects is most likely if the patient is a young child, and what is the underlying mechanism?

Accepted Answer

Brown discoloration of teeth because tetracycline binds to calcium in developing teeth.

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

$$191,000$$ 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

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 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 evolved from prokaryotic ancestors and have ribosomes similar to bacterial ribosomes.

Question 10

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

Accepted Answer

Attachment → Uncoating → Assembly → Lysis

Question 11

A patient with a history of multiple severe allergic reactions is exposed to an allergen for the second time. Which antibody is primarily responsible for the rapid onset of anaphylaxis, and what is its mechanism?

Accepted Answer

IgE; binds to mast cells causing degranulation and histamine release.

Question 12

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

Accepted Answer

They act as a link between the innate and adaptive immune systems by activating B cells and cytotoxic T cells.

Question 13

Which of the following is a major risk associated with the use of DNA replication inhibitors such as ciprofloxacin?

Accepted Answer

Tendon rupture and seizures due to GABA receptor blockage

Question 14

A patient is exposed to poison ivy and develops a rash 48 hours later. Which type of hypersensitivity reaction is this, and what is the primary immune mechanism involved?

Accepted Answer

Type IV; T cell-mediated cytotoxicity and macrophage activation

Question 15

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 16

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

Accepted Answer

IgM; pentamer

Question 17

A patient receives an antivenom and subsequently develops nephritis due to immune complex deposition in the kidneys. Which type of hypersensitivity reaction is this, and what is the underlying process?

Accepted Answer

Type III; immune complexes accumulate in capillaries causing inflammation

Question 18

Which of the following best describes the process of opsonization?

Accepted Answer

Antibodies bind to pathogens, making them easier for phagocytes to engulf.

Question 19

Which of the following is true regarding the Major Histocompatibility Complex (MHC) in human cells?

Accepted Answer

Macrophages and dendritic cells express MHC II.

Question 20

A newborn is at risk for hemolytic disease of the newborn (erythroblastosis fetalis) if which of the following conditions are met?

Accepted Answer

Mother is Rh- and baby is Rh+ during the second pregnancy

Microbiology Study Guide: Viruses, Antibiotics, Immune System, and Hypersensitivity

Study Guide - Practice Questions

Study Guide - Flashcards