Question

Common cold is not cured by antibiotics because it is
A. Caused by a gram negative bacterium
B. Not an infectious disease.
C. Viral infection
D. Caused by a gram positive bacterium

Answer 1

Hint:- Antibiotic medicines are drugs that are active against the action of bacteria. Antibiotics means against life. Antibiotics were invented by Alexander Fleming. An antibiotic either kills the bacterium or inhibits its action. The antibiotics that kill the bacteria are called bactericidal antibiotics and the antibiotics which inhibit their action are called bacteriostatic antibiotics.

Complete solution:
The common cold is a very common infectious disease of humans. It is caused mainly by rhinoviruses. The common cold syndrome is also caused by other viruses affecting the respiratory tract like influenza, adeno, corona viruses. Antibiotics are not effective in curing a common cold as it is a viral infection. The virus in droplets can be transferred through hand to hand contact, sneezing, coughing, etc. The virus enters the respiratory tract and gets attached to the receptors on ciliary epithelial cells in the nasal cavity and causes damage to the cells facilitating secondary bacterial infections. The symptoms of the disease are running nose, sore throat, headache, etc.
Bacteria are divided into gram-positive and gram-negative based on the gram staining properties. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall and are stained violet in colour on gram staining. Gram-negative bacteria have a thin peptidoglycan layer and are stained in reddish-pink colour on Gram staining.
So, the correct answer is option C.

Note:- Viral infections can cause secondary bacterial infections. That is, when the virus enters the body, it damages the respiratory epithelial cells and immunity of the organism decreases thereby facilitating the easy entry and attachment of bacteria on the respiratory tract. Pneumonia is a common secondary bacterial infection in the respiratory tract. These secondary infections can be prevented by the use of antibiotics during viral infections.