Question

Describe the mechanism of action of antibiotics.

Answer 1

Hint: The action of antibiotics biochemically takes place. The drug binds with an enzyme targeting the area or cells. The antibiotic action takes place mainly in four ways.

Complete answer:
Injuring the cell membrane. The plasma membrane is permeable and they help in the transportation of proteins. When these selectively permeable membranes are disrupted by the antibiotics, the ions of the cells are lost and distorted. There is an influx of water into the cell which leads to swelling of cells and then cell lysis. This is done by penicillin.
The effect of antibiotics against the cell wall. Some reactions in the cell membrane are catalyzed by penicillin-binding proteins construct peptidoglycan. Certain antibiotics react with penicillin-binding proteins and inhibit the cross-linking of peptidoglycan. Thus, the microorganisms are killed by these cell wall inhibitors. Like in cephalosporins and carbapenems.
Inhibition of protein synthesis. In the ribosome, the protein is translated from mRNA to tRNA. Puromycin mimics tRNA and enters the ribosome and it is toxic to humans and animals. Antibiotics like Erythromycin, Chloramphenicol inhibit the binding of Puromycin. This is done by inactivating the gene. The aminoglycosides inhibit the 30s subunit of the ribosome. The macrolides bind with the 50s subunit of the ribosome and inhibit protein synthesis.
Inhibiting DNA duplication. The inhibition of topoisomerases interferes with DNA unwinding and further transcription and translation is stopped. This is seen in quinolones like ciprofloxacin.

Note:
The mechanism of action of antibiotics describes the biochemical process at the molecular level. Antibiotics are very active in multiplying cells and many of the cellular activities. Thus, the organism undergoes cellular damage and finally death.