NEET BIOLOGY

Detailed explanation-1: -Gram-positive bacteria lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives. Threading through these layers of peptidoglycan are long anionic polymers, called teichoic acids.

Detailed explanation-2: -Gram positive bacteria have a thick peptidoglycan layer and no outer lipid membrane whilst Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

Detailed explanation-3: -Gram-positive organisms have a thicker peptidoglycan cell wall compared with gram-negative bacteria. It is a 20 to 80 nm thick polymer while the peptidoglycan layer of the gram-negative cell wall is 2 to 3 nm thick and covered with an outer lipid bilayer membrane.

Detailed explanation-4: -Most Gram-positive bacteria have a relatively thick (about 20 to 80 nm), continuous cell wall (often called the sacculus), which is composed largely of peptidoglycan (also known as mucopeptide or murein).

Detailed explanation-5: -The thickened peptidoglycan layer in Gram positive cells allows them to retain the stain (hence remaining ‘stain positive’ or ‘Gram positive) where as the thin layer seen in Gram negative cells cannot prevent the stain from leeching out (hence stain and Gram negative).