Characteristics of Gram positive and Gram Negative Bacteria

Characteristics of Gram positive and Gram Negative Bacteria Gram positive bacteria Gram negative bacteria Characteristic Gram stain color Relative thickness of tid Teichoic acid Could be a bacillus Could be a coccus Could be a spirillum Capsule present outer membrane present LPS present Plasmids present Some members form Produce exotoxins Associated with endotoxin Flagellum(a) present Pathogenic? Contains DNA Contains RNA Motile Contains a PM Contains 70S ribosomes

Solution

Characteristic Gram positive Gram negative Gram stain colour Violet (due to cryatal violet) Pink or Red( due to safranin) Relative thickness of peptidoglycan relatively thicker peptidoglycan layer thinner peptidoglyacan layer than that of gram positive bacteria Teihoic acid present along with lipoids that form lipoteichoic acids which acts as chelating agents facilitating cell to cell adherence absent Bacillus Yes Yes Coccus Yes either free or in bunches Yes either free or in bunches Sprillum yes No Capsule capsular layer is observed above the lipopolysaccharide layer in some species Capsules are generally absent Outer membrane formed of peptidoglycan layer cross linked by bacterial enzyme transpeptidase present and consists of LPS LPS Absent Present Plasmids present Present Endospores Since they are capsulated they may be capable of endospore formation Relatively less spore formation Exotoxins Maybe Maybe Endotoxins Flagellum(a) if present will have 2 basal rings to support if Present have 4 basal rings to support Pathogenicity Less pathogenic More pathogenic DNA Present Present RNA Present Present Motility Motile in case of flagellates Motile in case of flagellates