Major Difference Between Gram-Positive and Gram-Negative Bacteria

Gram positive

Gram negative

Cell wall thickness - 150-200Å.

Cell wallthickness - 75-120Å

Number of layer of cell wall - single

Number of layer of cell wall - two

Cell wall is smooth and in contact with cell membrane thoroughly.

Cell wall is wavy and in contact with cell membrane only at few places.

Lipid content in cellular envelop - 2-4%

Lipid content in cell wall is 20-30%

Peptidoglycan contents - 70-95%

Peptidoglycan contents - 5-20%

Amount of Amino sugars - 10-20%

Amount of Amino sugars - 2-8%

Mesosome - Commonly present

Mesosome - less common

Pili - rarely present

Pili - commonly present

Mostly they are coccus

Mostly bacilli

Generally non-capsulated

Generally capsulated

Flagellation - less common

Flagellation - common

Teichoic acid - present

Teichoic acid - absent

Produce exotoxin

Produce endotoxin

Susceptible to penicillin, sulfonamide, drugs acriflavine, low surface tension, anionic detergents

Susceptible to streptomycin, gentamycin, tetracycline and kanamycin.

Diaminopimelic acid - absent

Diaminopimelic acid - present

In cell wall, porins - absent

In cell wall porins - present

Pathogenic forms - less common

Pathogenic forms - common