Question

Which of the following differentiates gram positive and gram negative bacteria?

• A. A liposaccharide, outer covering with a small peptidoglycan component in the cell wall.
• B. A small peptidoglycan, component covering a large liposaccharide base.
• C. A large peptidoglycan, component in the cell wall.
• D. A cell wall composed of liposaccharide and chitin.
• E. A cell wall composed of chitin over peptidoglycan.

Answer 1

Answer: (C)

A large peptidoglycan, component in the cell wall.

The gram-negative cell wall is characterized by the presence of an outer membrane, a thinner peptidoglycan layer, and an extensive periplasmic space surrounding the peptidoglycan. The uppermost layer of the outer membrane has lipopolysaccharide while the innermost layer is a typical lipid layer. Gram-positive cells are characterized by the presence of a single thick layer of cell wall which is made up of peptidoglycan, teichoic acid, and lipoteichoic acid. They lack outer membrane and porin and have narrow periplasmic space.

So, the correct answer is C.