Question 1

Which of the following best describes the difference between horizontal and vertical gene transfer in bacteria?

Accepted Answer

Horizontal gene transfer involves the transfer of genetic material between unrelated bacteria, while vertical gene transfer is the transmission of genetic material from parent to offspring.

Question 2

A patient is diagnosed with a bacterial infection caused by a bacterium that acquired antibiotic resistance through a process involving a bacteriophage. Which genetic mechanism is most likely responsible?

Accepted Answer

Transduction

Question 3

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are extrachromosomal DNA elements that can carry genes for antibiotic resistance, virulence, or metabolic functions.

Question 4

Which of the following mutagenic agents is most likely to cause thymine dimers in DNA?

Accepted Answer

UV radiation

Question 5

A microbiologist is using the G+C ratio to classify a newly discovered bacterium. What does a high G+C ratio indicate?

Accepted Answer

The bacterium is more likely to be classified as an Actinobacteria.

Question 6

Which of the following is NOT a characteristic used to classify viruses?

Accepted Answer

Presence of a cell wall

Question 7

A dimorphic fungus is most likely to exist as a yeast at which temperature?

Accepted Answer

$$37^\circ C$$

Question 8

Which of the following best describes the function of viral neuraminidase (NA) in influenza viruses?

Accepted Answer

It cleaves sialic acid residues to facilitate the release of new virions from the host cell.

Question 9

Which of the following is a correct sequence of Koch’s postulates?

Accepted Answer

1. The microorganism must be found in all cases of the disease. 2. It must be isolated and grown in pure culture. 3. The cultured microorganism must cause disease in a healthy host. 4. It must be reisolated from the experimentally infected host.

Question 10

A hospital patient develops a urinary tract infection after catheterization. This infection is best classified as:

Accepted Answer

Nosocomial

Question 11

Which of the following best describes the difference between a protozoan trophozoite and a cyst?

Accepted Answer

A trophozoite is the active, feeding stage, while a cyst is the dormant, resistant stage.

Question 12

Which of the following is a characteristic of Chlamydiae that differentiates it from Rickettsia?

Accepted Answer

Chlamydiae do not require arthropod vectors for transmission.

Question 13

A patient presents with symptoms of malaria. In which human organ does the exoerythrocytic cycle of Plasmodium occur?

Accepted Answer

Liver

Question 14

Which of the following best describes the structure of a typical viral icosahedron?

Accepted Answer

A polyhedral structure with 20 triangular faces and 12 vertices.

Question 15

Which of the following is a correct definition of the term 'mutation rate'?

Accepted Answer

The probability that a gene will mutate during a single cell division.

Question 16

Which of the following is a distinguishing feature of transposons compared to plasmids?

Accepted Answer

Transposons can move within and between DNA molecules, while plasmids replicate independently.

Question 17

A patient is diagnosed with a chronic viral infection. Which of the following viruses is most likely responsible?

Accepted Answer

Hepatitis B virus

Question 18

Which of the following best describes the difference between a monoecious and a dioecious helminth?

Accepted Answer

Monoecious helminths have both male and female reproductive organs in one individual, while dioecious helminths have separate male and female individuals.

Question 19

Which of the following is a correct definition of the term 'prevalence' in epidemiology?

Accepted Answer

The total number of cases of a disease in a population at a given time.

Microbial Genetics, Classification, Eukaryotic Microbes, Viruses, and Principles of Disease: Study Guide

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