Question

The main difference between Gram positive and Gram negative bacteria lies in the composition of

• A. Cilia
• B. Cell wall
• C. Cytoplasm
• D. Nucleolus

Answer 1

Answer: (B)

Gram positive bacteria differs from Gram negative bacteria as they have different components of cell wall. The cell wall of Gram positive bacteria contains a thick peptidoglycan layer with teichoic acids while the cell of Gram negative bacteria contains a thin peptidoglycan layer without teichoic acids. Gram positive bacteria can retain the gram stain and appear purple because the thick layer of peptidoglycan traps the stain. On the other hand, Gram negative bacteria appear bright pink or red because they have only a thin peptidoglycan layer sandwiched between two lipid layers.

So, the correct answer is option B.