Question

What is antibiotic penicillin? Give its function.

Answer 1

Antibiotics are important antibacterial substances which help in the reduction and prevention of infection by bacteria and other microbes.

Complete answer:
Antibiotics are chemical agents that can prevent infection by either killing the microbe or restricting the growth of the microbe.
The group of antibiotics obtained from Penicillium molds are known as penicillin.
The infection caused by staphylococci and streptococci was successfully prevented using the antibiotic penicillin.
The different types of penicillin include penicillin G, penicillin V, benzathine penicillin, and procaine penicillin.
The penicillin blocks the enzymes in bacteria that are responsible for cell wall formation in bacteria due to which the bacterial cell cannot form a strong cell wall and hence it fails to maintain proper osmotic gradient which results in the death of bacteria.

Some bacteria become resistant to penicillin due to their ability to breakdown the enzyme beta-lactamases and hence for such bacterias it becomes necessary to modify the antibiotics using substances like beta-lactamases inhibitors, clavulanic acid which prevents the bacteria to break the beta-lactamase enzyme.
The structure of penicillin includes a beta-lactam ring which is a four-membered ring that is attached to the thiazolidine ring which is a five-membered ring.

Note: Other types of antibiotics are cephalosporins, tetracyclines, aminoglycosides, sulfonamides, quinolones, and macrolides.
Penicillin was accidentally discovered by Alexander Flemming while working on staphylococcus aureus when he observed that a certain fungal substance killed the bacteria, and then he named that substance penicillin.