Question

In a gram stain, what are bacteria called when they retain the primary stain?

a) Gram-positive
b) Gram-negative
c) Acid-fast
d) Endospore-forming

Answer 1

In a gram stain, bacteria that retain the primary stain are called Gram-positive.

Step-by-step explanation:

In a gram stain, bacteria that retain the primary stain are called Gram-positive. The Gram stain is a commonly used method to differentiate between two major groups of bacteria based on their cell wall structure. Gram-positive bacteria have a thick peptidoglycan cell wall that retains the crystal violet stain, while Gram-negative bacteria have a thinner peptidoglycan layer that does not retain the stain and requires a counterstain. An example of Gram-positive bacteria is Bacillus species.