Question

1. Many antibiotics work by attacking various stages in the production of peptidoglycan in the cell wall of bacteria. Bacteria and Archaea are both prokaryotes that possess a cell wall. Yet antibiotics such as penicillin disrupts the cell wall of susceptible bacteria but generally do not affect Archaea at all. Why?

Answer 1

Bacteria and Archaea both are prokaryotes, but they belong to two different domains of life.

Antibiotics like Penicillin are effective against most of the Eubacteria. Penicillin antibiotics interfere with the cell wall synthesising machinary of the Eubacteria which contains Peptidoglycan. The penicillin like antibiotics have a beta- lactam ring which binds with the DD-Transpeptidase enzyme. This transpeptidase enzyme is responsible for cross- linking of the peptidoglycan in the cell wall of the bacteria. When the beta-lactam of the penicillin binds this enzyme, it inhibits it's action and thus new cell wall is not synthesized in the bacteria and thus bacterial population is controlled.

On the other hand the Archaea do not have peptidoglycan in their cell walls and hence can continue their cell wall synthesis even in presence of the antibiotics such as penicillin and are thus antibiotic resistant.