PCAT Microbiology 2

Question 1

Which bacterial structure is the primary determinant of Gram stain results?

Accepted Answer

Peptidoglycan layer thickness

Answer

Gram-positive bacteria have a thick peptidoglycan layer that retains crystal violet, while Gram-negative bacteria have a thin layer that is decolorized.

Question 2

A bacterium that can grow at refrigerator temperatures (4°C) is classified as a:

Accepted Answer

Psychrophile

Answer

Psychrophiles (cold-loving organisms) thrive at low temperatures ranging from -5°C to 20°C, with an optimum around 15°C.

Question 3

Which mechanism allows bacteria to acquire antibiotic resistance genes from the environment through DNA uptake?

Accepted Answer

Transformation

Answer

Transformation involves uptake of naked DNA from the environment; naturally competent bacteria can incorporate these genes into their chromosome.

Question 4

The Kirby-Bauer disk diffusion test measures:

Accepted Answer

Antibiotic susceptibility via zone of inhibition

Answer

The Kirby-Bauer test places antibiotic-impregnated disks on an inoculated agar plate; the diameter of the clear zone indicates susceptibility.

Question 5

Which viral enzyme enables RNA viruses to replicate their genome without using DNA as an intermediate?

Accepted Answer

RNA-dependent RNA polymerase

Answer

RNA-dependent RNA polymerase (RdRp) uses an RNA template to synthesize new RNA strands, allowing RNA viruses to replicate independently of DNA.

PCAT - Pharmacy College Admission Test Practice Test

PCAT - Pharmacy College Admission Test Practice Test

PCAT Microbiology 2