Question

Diphtheria is caused by

(a) poisons released by living bacterial cells into the host tissue 

(b) poisons released from dead bacterial cells into the host tissue 

(c) poisons released by virus into the host tissues 

(d) excessive immune response by the host's body

Answer 1

The correct option is (a) poisons released by living bacterial cells into the host tissue.

Explanation:

Toxins released from Corynebacterium diphtheriae cause diphtheria. Actually, bacterial cells do not contain gene for toxin production, i.e. a phage carries the gene for it. Only those lysogenised cell of C, diphtheriae which carry p-phage, can produce the toxin and cause diphrheria.