Download Gram-Negative Bacteria - Mrs. Yu`s Science Classes

GramNegative
Bacteria
Ellim Kim
What is
Gram-Negative Bacteria?
Violet = gram-positive
Red = gram-negative

Bacteria (Kingdom: Eubacteria) that do not
retain crystal violet dye in the Gram staining
protocol

Gram staining differentiates bacteria by the
chemical and physical properties of their cell
walls by detecting peptidoglycan, which is
present in a thick layer in Gram-positive
bacteria
General Characteristics

Aerobic rods with flagella at the poles
General Characteristics

Excrete extracellular pigment by diffusing it
into the local environment
General Characteristics

Ability to use nitrate (NO3-) instead of
oxygen as a final electron acceptor

Process of anerobic respiration yields
considerable energy

Could be a problem because it robs the
soil of nitrate in the metabolism
Example :: E. Coli

Most E. colis strains are harmless, but some
stereotypes can cause serious food
poisoning in humans

Thought to be associated with food
poisoning

Pathogenic strains of the bacterium cause
disease