Question

Student to attempt either option (A) or (B):
(A) How does a human body respond when vaccine is introduced into it? It is said that vaccinations are a must for a healthy society. Justify.
OR
(B) Humans have innate immunity for protection against pathogens that may enter the gut along with food. What are the two barriers in our body that protect it from such pathogens?

Hint:

Vaccines build immunity and memory cells. Mucus and stomach acid guard the gut against pathogens.

Answer 1

(A) Step 1: A vaccine introduces weakened or inactivated pathogens or their antigens into the body.
Step 2: The immune system recognises these as foreign and activates B-lymphocytes to produce antibodies.
Step 3: Memory cells are also formed for long-lasting immunity.
Step 4: This ensures quicker and stronger response upon future exposure to the same pathogen.
Conclusion: Vaccination prevents the spread of infectious diseases, protecting both individuals and society (herd immunity).
OR
(B) Two barriers protecting the gut:

1. Physical barrier: Mucus lining in the gut that traps microbes and prevents their entry.
2. Physiological barrier: Hydrochloric acid in the stomach that kills most microbes entering with food.