Consider the following statements regarding antibiotics: 1, They are used to destroy disease causing bacteria. 2. They can be applied to the skin, swallowed or injected to fight micro-organisms inside the body, 3. They are effective against disease-causing viruses. 4. The first antibiotic to be discovered was tetracycline. Which of the statements given above is/are correct ?

Antibiotics are substances used to destroy or inhibit the growth of disease-causing bacteria [1]. They are administered through various routes depending on the infection, including topical application to the skin, oral ingestion (swallowing), or injection to fight microorganisms inside the body [1]. However, antibiotics are specifically designed to target bacterial cell structures and are not effective against viruses, such as those causing the common cold or influenza [2]. Regarding their history, the first antibiotic discovered was penicillin by Alexander Fleming in 1928, not tetracycline [1]. Tetracyclines were introduced much later, around 1950, during the 'golden era' of antibiotic discovery [3]. Therefore, statements 1 and 2 are correct, while statements 3 and 4 are incorrect.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Discovery of the first antibiotic, Penicillin > p. 40
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > 3.5.1 Treatment of diseases > p. 39
3. [3] https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/autolysin