California Cosmetology Written ExamSafety and Infection ControlEasy
A lab report describes bacteria that cause strep throat and certain skin infections, noting that under a microscope they appear as round bacteria arranged in curved chains. Which classification is being described?
- AStreptococci
- BBacilli
- CStaphylococci
- DDiplococci
Show answer & explanationAnswer & explanation
Correct answer: A. Streptococci
Streptococci are round bacteria (cocci) that form chains and are associated with strep throat and skin infections. Staphylococci form clusters, diplococci form pairs, and bacilli are rod-shaped, not round.
Why the other options are wrong
- B. Bacilli are rod-shaped bacteria, a different shape category entirely.
- C. Staphylococci grow in grape-like clusters, not chains.
- D. Diplococci occur in pairs, not chains.
Streptococci
Round bacteria that grow in chain formations, associated with infections such as strep throat.
- Chain arrangement of cocci
- Cause strep throat and some skin infections
- One of three main coccus arrangements
Memory trick: 'Strep' sounds like 'string' — a string/chain of beads.