Free CMT Microbiology Questions and Answers

Question 1

Which staining technique is used to classify bacteria as Gram-positive or Gram-negative?

Accepted Answer

Gram stain

Answer

The Gram stain is a fundamental differential staining technique used in microbiology to classify bacteria into two large groups: Gram-positive and Gram-negative. This classification is based on differences in their cell wall composition, specifically the thickness of the peptidoglycan layer, which affects how they retain the crystal violet stain. This distinction is crucial for guiding antibiotic treatment.

Question 2

Which bacteria is most commonly associated with urinary tract infections?

Accepted Answer

Escherichia coli

Answer

Escherichia coli (E. coli) is by far the most common bacterial cause of urinary tract infections (UTIs), accounting for 80-90% of cases. This bacterium, a normal inhabitant of the human gastrointestinal tract, can ascend the urethra and colonize the bladder, leading to infection. Its prevalence in UTIs makes it a critical pathogen in clinical microbiology.

Question 3

What medium is used to culture Mycobacterium tuberculosis?

Accepted Answer

Lowenstein-Jensen medium

Answer

Lowenstein-Jensen (LJ) medium is a specialized egg-based culture medium specifically formulated for the isolation and cultivation of Mycobacterium tuberculosis and other mycobacteria. It contains malachite green to inhibit the growth of other bacteria and provides the necessary nutrients for the slow-growing mycobacteria. Culturing on LJ medium is a standard method for diagnosing tuberculosis.

Question 4

What structure enables bacterial mobility?

Accepted Answer

Flagella

Answer

Flagella are long, whip-like appendages that extend from the cell body of many bacteria and are primarily responsible for bacterial motility. They rotate like propellers, enabling bacteria to move through liquid environments towards nutrients or away from toxins. Other structures like capsules and pili have different functions, such as adherence or protection.

Question 5

Which viral infection is diagnosed using the rapid antigen test?

Accepted Answer

Influenza

Answer

Rapid antigen tests are commonly used for the quick diagnosis of influenza virus infections. These tests detect specific viral proteins (antigens) directly from respiratory samples, providing results within minutes. While generally less sensitive than PCR, their speed and ease of use make them valuable for immediate clinical decision-making and public health surveillance during flu season.

CMT - Certified Medical Technologist Practice Test

CMT - Certified Medical Technologist Practice Test

Free CMT Microbiology Questions and Answers