Question

xompare and contrast the cell walls of fram postuve and gram negative bacteria. why are the drugs that target cell wall synthesus useful? are drugs that target cell wall synthesus effective for all bacteria

Answer 1

The gram positive bacteria has a thick cell wall made of peptidoglycan and it is multilayered which consists of technoic acid. It is able to retain crystal violet dye and hence stain purple which helps in its identification by gram staining. The gram negative bacteria has a a single layered thin cell wall with no techoic acid but the cell wall is protected with a outer membrane made of lipopolysacccharide. The gram negative bacteria stain red or pink but are not able to retain the stain when washed with alcohol.

Peptidoglycan is basically the backbone of the cell wall and it helps in stabilizing the structure of the cell. It is a polymer that contains amino acid and sugars which binds together and the amino acid forms peptide cross – linking with help of transpeptidase enzyme. The drugs with beta-lactam ring like penicillin are effective against gram positive bacteria as it binds via the beta lactam ring to the transpeptidase and weakens the peptide cross linking. This weakens the cell wall and disrupts it causing lysis of the cell. The gram negative bacteria is not effective as it is not able to cross the outer lipid membrane to break the peptide cross link.