Question

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

Answer 1

Antibiotics are medicines that cure infections caused by bacteria. Antibiotics act either by disrupting the structures in bacterial cells or by disturbing the essential processes of bacteria.

Complete answer:
Option A: Common cold is a viral infection of the nose and throat. Common cold can be caused by many different viruses. Antibodies kill or slow down bacteria but are not helpful in fighting viruses. Therefore this is the correct option.
Antibiotics have a spectrum of bacteria upon which they can act on. They target either cell walls or membranes that surround the bacteria or the machinery that makes DNA and RNA or protein-producing machinery. Since viruses don't have a defined cell and their genetic material keeps mutating, the antibiotics cannot target them or act upon them.
Option B: Gram-positive bacteria are those which have a thick peptidoglycan layer in their cell wall. They retain the color during the gram staining process. The common cold is not caused by gram-positive bacteria. Therefore, this is the incorrect option.
Option C: Gram-negative bacteria don't retain the stain during gram staining because their cell walls lack the thick peptidoglycan layer. The common cold is not caused by gram-negative bacteria. Therefore, this is the incorrect option.
Option D: Common cold is an infectious disease. Therefore, this is the incorrect option. It occurs with symptoms such as a runny nose, sore throat, cough, headache, and sneezing.

Hence,the correct answer is option ‘A’, caused by a virus.

Note: The common cold is usually harmless with symptoms such as a runny nose, sore throat, cough, and sneezing. Most people recover within a week or 10 days. It spreads easily through airborne respiratory droplets, contact with contaminated surfaces, and contact with infected people. Not the disease, but symptoms are treated through anti-inflammatory drugs and decongestants.