Question 1

Which of the following best describes the structure of a typical enveloped virus, as shown in the first image?

Accepted Answer

A core of nucleic acid surrounded by a protein capsid, with an outer lipid envelope containing glycoprotein spikes.

Question 2

Which laboratory technique is most appropriate for rapidly diagnosing a Rotavirus infection in a child with severe diarrhea?

Accepted Answer

ELISA for viral antigen in stool sample

Question 3

Which of the following is a key difference between the replication cycles of bacteriophages and animal viruses?

Accepted Answer

Animal viruses may enter host cells by endocytosis or membrane fusion, while bacteriophages inject their nucleic acid into the host.

Question 4

Which of the following viruses is associated with the development of cervical cancer?

Accepted Answer

Human Papillomavirus (HPV) types 16 and 18

Question 5

What is the main reason why smallpox was successfully eradicated worldwide?

Accepted Answer

Smallpox has no animal reservoir and an effective vaccine was available.

Question 6

Which of the following best describes the action of prion PrP in prion diseases?

Accepted Answer

It induces abnormal folding of normal cellular prion proteins, leading to neurodegeneration.

Question 7

Which of the following statements about antigenic drift and antigenic shift in Influenza viruses is correct?

Accepted Answer

Antigenic drift involves small, gradual mutations in viral genes, while antigenic shift involves major genetic reassortment resulting in new viral subtypes.

Question 8

A patient presents with jaundice, fatigue, and elevated liver enzymes. Laboratory tests reveal the presence of both HBsAg (Hepatitis B surface antigen) and anti-HBc (antibody to Hepatitis B core antigen). What does this indicate?

Accepted Answer

The patient is currently infected with Hepatitis B virus.

Question 9

Which of the following is a common opportunistic infection associated with AIDS patients?

Accepted Answer

Pneumocystis pneumonia

Question 10

Which of the following best describes the transmission of Leishmania, as depicted in the second image?

Accepted Answer

By the bite of infected sand flies

Question 11

Which stage of protozoan parasites is typically responsible for transmission and environmental survival?

Accepted Answer

Cyst

Question 12

Which of the following best explains why helminths are studied in microbiology?

Accepted Answer

Their eggs and larvae are microscopic and cause significant human disease.

Question 13

Which of the following is the definitive host in the life cycle of Plasmodium (malaria)?

Accepted Answer

Mosquito

Question 14

A patient presents with watery diarrhea after swimming in a public pool. Acid-fast staining of a stool sample reveals oocysts. Which organism is most likely responsible?

Accepted Answer

Cryptosporidium parvum

Question 15

Which of the following best describes the function of reverse transcriptase in retroviruses such as HIV?

Accepted Answer

It synthesizes DNA from an RNA template.

Question 16

Which of the following is a key reason why there is no vaccine for Hepatitis C virus (HCV)?

Accepted Answer

HCV exhibits high genetic variability, making vaccine development difficult.

Question 17

Which of the following best describes the transmission of Toxoplasma gondii to humans, as shown in the fifth image?

Accepted Answer

Ingestion of oocysts from contaminated food, water, or cat feces

Question 18

Which of the following is a characteristic of prions that differentiates them from viruses?

Accepted Answer

Prions lack nucleic acid and are composed only of protein.

Question 19

Which of the following is the most common method of transmission for Enterobius vermicularis (pinworm)?

Accepted Answer

Ingestion of eggs from contaminated hands or surfaces

Question 20

Which of the following best describes the role of the CCR5-delta 32 mutation in HIV infection?

Accepted Answer

It confers resistance to HIV infection by preventing viral entry into host cells.

Characterizing Viruses, Pathogenic DNA and RNA Viruses, and Parasitic Eukaryotes

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