Problem 69 - A Complete Resource Book in Chemistry for JEE Main

Question

Point out the correct statements about antibiotics. (1) pencillin was discovered by Fleming (2) phenactine is a very important antibiotic (3) they are used in the treatment of infections diseases (4) they are produced by various organisms and fungi (a) 1,2 and 3 (b) 1,2 and 4 (c) 1,3 and 4 (d) 2,3 and 4

Step-by-Step Solution

Answer

The correct option is (c) 1, 3, and 4.

Step 1: Analyze Statement 1

Assessing the statement: "Penicillin was discovered by Fleming." Sir Alexander Fleming is indeed credited with the discovery of penicillin in 1928. Therefore, this statement is correct.

Step 2: Analyze Statement 2

Assessing the statement: "Phenactine is a very important antibiotic." Phenacetin (commonly misspelled as Phenactine) is not an antibiotic; it is a pain-relieving and fever-reducing drug. Thus, this statement is not correct.

Step 3: Analyze Statement 3

Assessing the statement: "They are used in the treatment of infectious diseases." Antibiotics are primarily used to treat bacterial infections, making this statement accurate.

Step 4: Analyze Statement 4

Assessing the statement: "They are produced by various organisms and fungi." Many antibiotics are indeed produced by microorganisms and fungi, such as penicillin from the mold Penicillium. Therefore, this statement is correct.

Step 5: Determine Correct Option

After analyzing all the statements, the correct ones identified are 1, 3, and 4. These correspond to option (c) in the given choices.

Key Concepts

Penicillin Discovery

In 1928, Sir Alexander Fleming made a groundbreaking discovery—penicillin, which would later revolutionize the field of medicine. While working at St. Mary’s Hospital in London, he observed that a mold called *Penicillium notatum* had contaminated one of his petri dishes. Remarkably, he noticed something unusual: the bacteria in close proximity to the mold were being destroyed, leaving clear areas in the dish. This serendipitous observation led to the identification of penicillin, the first true antibiotic. Fleming's insight into the potential of penicillin marked the beginning of a new era in the treatment of bacterial infections. It took several more years of research by other scientists to develop it for widespread medical use, but Fleming's discovery paved the way for countless lives to be saved.

Antibiotic Functions

Antibiotics are powerful medications designed to combat bacterial infections. They function primarily by killing bacteria or preventing them from multiplying. Here's how antibiotics work:

• **Cell Wall Inhibition:** Some antibiotics, like penicillin, target the bacteria's cell wall, causing it to break down and ultimately killing the bacteria.
• **Protein Synthesis Disruption:** Others interfere with protein production, which is essential for bacterial growth and reproduction. Without proteins, bacteria cannot function or multiply.
• **Nucleic Acid Interference:** Certain antibiotics inhibit DNA replication and transcription, preventing bacteria from reproducing.

It's crucial to note that antibiotics are ineffective against viral infections. This distinction is vital in medical treatment to ensure proper use of these drugs. Overuse or misuse of antibiotics can lead to antibiotic resistance, a significant challenge in modern healthcare.

Microorganism-produced Antibiotics

The vast majority of antibiotics are derived from microorganisms, particularly bacteria and fungi. These organisms produce antibiotics naturally, which they use to fend off competing microbes in their environment. For instance:

• *Penicillium* molds, as in the case of penicillin, produce substances that inhibit other bacteria.
• Bacteria of the genus *Streptomyces* are notable for producing many antibiotics, including streptomycin, which was the first effective treatment for tuberculosis.

These naturally occurring compounds have been harnessed by humans to treat a wide range of bacterial infections. Through processes like fermentation, pharmaceutical companies produce antibiotics on a large scale to meet medical needs. The natural production of antibiotics by microorganisms underscores the complexity of microbial ecosystems and their impact on human health.