Question

Arrange in order of action.

(i) Activation of helper T cells

(ii) Release of cytokines

(iii) Activation of killer T cells

(iv) Release of perforins

(v) Bursting of infected cells

• A. ii, i, iv, iii, v
• B. i, ii, iii, iv, v
• C. ii, iii, iv, i, v
• D. i, iv, iii, ii, v

Answer 1

The correct option is B

i, ii, iii, iv, v

Macrophages engulf viral particles and display the viral peptides on their cell surface. The helper T cell binds to the macrophage, and gets activated or is “switched on”. Upon activation, the helper T cells divide and release chemicals called cytokines. Cytokines activate killer T cells to attack. Killer T cells release special enzymes called perforins, which bore channels through the infected cell membranes. This allows water to rush in, causing these cells to swell, break apart and die.