Question

Prokaryotes stain as Gram-positive or Gram-negative because of differences in the cell _______.

a. wall

b. cytoplasm

c. nucleus

d. chromosome

Short answer

Prokaryotes stain differently as gram-negative or positive based on the difference in the cell wall.

Step-by-step solution

Explanation

Prokaryotic bacteria are grouped into two groups on the basis of gram stain they take (red or violet). The bacterial group which takes the stain of crystal violet and stain as violet is the gram-positive bacteria as their cell wall is made up of a thick peptidoglycan layer with no outer lipid layer., while the gram-negative group of bacteria have the thin peptidoglycan layer and an outer lipid layer, the cells of these groups doesn't take the crystal violet stain but take the counterstain and stain as red or pink. This helps in distinguishing between gram-positive and gram-negative bacteria.

Final answer

Hence, the option 'a' is correct.