Question

Which among the following is an antibiotic?

A. Sodium Bicarbonate

B. Streptomycin

C. Alcohol

D. Yeast

Answer 1

Hint: An antibiotic is a substance that kills or inhibits the growth of bacteria. In nature, it is produced by soil bacteria or fungi. They are also known as antibacterial substances. 

Complete answer:

An antibiotic is a kind of antimicrobial drug which is used to prevent bacterial infections and protozoan infections (sometimes). When an antibody is induced in an organism’s system, it either kills the bacteria or inhibits it from causing infections. As Streptomycin is used to treat a bacterial infection, it is regarded as an antibiotic.

Streptomycin was first isolated by Albert Schatz (who was a Ph.D. student at Rutgers University) on October 19, 1943.

The formula for Streptomycin is $C_{21}H_{39}N_7O_{12}$ and it is produced by Streptomyces griseus.

Streptomycin like any other antibiotic binds to the ribosome of the bacteria. To be specific, it binds to 16S rRNA of the 30S subunit present at the bacterial ribosome. Due to this, a compound known as formyl-methionyl-tRNA cannot bind to the 30S subunit and leads to inhibition of initiation (this step involves the binding of the smaller ribosomal subunit to the start of the mRNA sequence) and elongation (in this step the amino acids are brought to ribosomes by tRNAs and are linked together in a form of chain) steps of protein synthesis. As there is no protein synthesis the bacterial cell dies.

Streptomycin is used to treat bacterial infections like Tuberculosis (it is caused by Mycobacterium tuberculosis), plague, etc., in humans. It is also used to kill Gram-negative bacteria in animals.

Streptomycin is induced in the body with the help of injection which is given intravenously (in veins) or intramuscularly (in muscle).

Apart from that, there are several side effects of Streptomycin which include vomiting, pain, or irritation at the injection site (this is the site where the injection was injected), swelling, rash, tiredness, etc.

Hence, Option (B) is the correct answer.

Note: Antibiotics are used to treat bacterial infections and sometimes protozoan infection. They cannot be used in the case of fungal or viral infection. For example – cold, flu, and most coughs are treated by antibiotics.