Antibiotics
ஆன்டிபயாடிக்குகள்
Antibiotics are not magic bullets; they are chemical weapons in an evolutionary arms race. Do not confuse them with antibodies, a common blunder in the exam hall. If you cannot distinguish between microbial antagonism and host immunity, you are not ready for the NEET paper.
The idea
Antibiotics are chemical substances produced by specific microbes that inhibit or kill other pathogenic microorganisms. Alexander Fleming discovered Penicillin, the first antibiotic, while working on Staphylococci. These substances are vital in treating deadly diseases like plague, whooping cough, diphtheria, and leprosy. They function by disrupting the metabolic pathways or cell wall synthesis of target pathogens.
Why it matters
Microbes produce these chemicals as a competitive mechanism to inhibit the growth of rival microorganisms in their environment.
NEET lens
NEET focuses on the origin of Penicillin and its role in World War II. Memorize the names of the scientists: Fleming, Chain, and Florey. Expect match-the-following questions linking antibiotics to their source microbes. Never ignore the distinction between bacteriostatic and bactericidal actions.
Clinical significance
When antibiotics fail, we face the crisis of multi-drug resistant (MDR) bacteria. Overuse leads to selective pressure, allowing resistant strains to dominate the population. Without effective antibiotics, routine surgeries and minor infections become life-threatening risks.
Introduction
Antibiotics are chemical substances produced by some microbes that can kill or retard the growth of other (disease-causing) microbes. They were one of the most significant discoveries of the twentieth century.
Core concept
Discovery: Alexander Fleming, while working on Staphylococci bacteria, observed a mould growing in one of his unwashed culture plates, around which Staphylococci could not grow. He found that this was due to a chemical produced by the mould, which he named Penicillin after the mould Penicillium notatum. Its full potential as an effective antibiotic was established much later by Ernest Chain and Howard Florey. Penicillin was used extensively to treat American soldiers wounded in World War II. Fleming, Chain and Florey were awarded the Nobel Prize in 1945. Antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough (kali khansi), diphtheria (gal ghotu) and leprosy (kusht rog).
Go deeper
'Anti' means against and 'bio' means life; antibiotics are against disease-causing organisms. Misuse of antibiotics can select for antibiotic-resistant bacteria — an example of evolution by anthropogenic action.
From Class 10
Antibiotics are medicines that kill bacteria. The first one, penicillin, came from a mould.