Question

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Identify whether the following are true of Gram-positive or Gram-negative bacteria. Has a cell wall Has a second outer membrane Contains the molecule LPS, which triggers an immune response through TLR proteins Contains the bacteria that cause cholera Ampicillin and amoxicillin are specific to this type as they block peptidoglycan production

Answer 1

1)Both gram negative and gram positive bacteria posses cell wall.In gram negative bacteria in gram negative it is composed of thin peptidoglycan which is present between inner cytoplasmic membrane and outer bacterial membrane while in gram positive bacteria it is composed of thick peptidoglycan layer.That's why gram positive bacteria retain stain even after washing but gram negative doesn't.

2)gram negative bacteria contain second outer membrane it is made up of lipopolysaccharide(which consist of lipid core polysaccharide and antigen O ) in its outer leaflet and phospholipid in inner leaflet.

3) Gram negative bacteria contain LPS molecule and trigger response through LTR proteins.The lipid portion of the LPS act as an endotoxin , when this bacteria enters circulatory system the lipid may act as a toxin.

4)cholera is caused by Vibrio cholerae and it is a gram negative comma shaped bacterium.

5) Gram negative bacteria are resistant to many drug and detergents.The outer membrane of these bacteria protects the from antibiotics.They are resistant to penicillin and lysozyme.However antibiotics like ampicillian and amoxicillian are prepared which inhibit the cross linkage of peptidoglycan in both the bacteria.