ANS:A - Alexender

Penicillin, an antibiotic drug, was discovered by Alexander Fleming. Penicillin is an antibiotic that was discovered by Alexander Fleming in 1928. Fleming, a Scottish bacteriologist, noticed that a mold called Penicillium notatum had contaminated one of his petri dishes and was killing the surrounding bacteria. This observation led to the identification of penicillin as the first true antibiotic, capable of treating bacterial infections.

Key Points about Penicillin:

1. Mechanism of Action: Penicillin works by inhibiting the synthesis of bacterial cell walls, causing the bacteria to burst and die, which is effective against a wide range of bacteria.
2. Historical Impact: The discovery of penicillin revolutionized medicine, paving the way for the development of other antibiotics and significantly reducing mortality from bacterial infections.
3. Development: Although Fleming discovered penicillin, it wasn’t until the early 1940s that it was mass-produced and widely used, thanks to the efforts of scientists like Howard Florey and Ernst Boris Chain during World War II.
4. Applications: Penicillin is used to treat various infections, including pneumonia, strep throat, and syphilis, among others.
5. Resistance: Over time, some bacteria have developed resistance to penicillin, leading to the need for new antibiotics and ongoing research in the field.