UPSC Prelims 2022 Q97: Science & Technology – Biology
Which one of the following statements best describes the role of B cells and T cells in the
human body?
- (a) They protect the body from environmental allergens.
- (b) They alleviate the body's pain and inflammation.
- (c) They act as immunosuppressants in the body.
- (d) They protect the body from the diseases caused by pathogens.
Answer: (d) They protect the body from the diseases caused by pathogens.
Explanation
B cells and T cells
B and T cells are lymphocytes, the core of the adaptive immune system.
They recognise specific pathogens and remember them.
| Cell | Made in | Matures in | Main job |
|---|---|---|---|
| B cell | Bone marrow | Bone marrow | Makes antibodies (humoral immunity) |
| Helper T cell | Bone marrow | Thymus | Coordinates the immune response |
| Killer (cytotoxic) T cell | Bone marrow | Thymus | Destroys infected and cancer cells |
| Memory B and T cells | Bone marrow | Bone marrow (B) or thymus (T) | Fast response on reinfection; basis of vaccines |
Answer: (d) They protect the body from the diseases caused by pathogens.
Why each option is right or wrong
- (a) Incorrect. Allergies are an overreaction involving IgE; protecting against allergens is not their main role.
- (b) Incorrect. Pain and inflammation relief comes from drugs like NSAIDs, not lymphocytes.
- (c) Incorrect. B and T cells drive immunity; they are not immunosuppressants.
- (d) CORRECT. B cells make antibodies and T cells kill infected cells, protecting against pathogens.
Key point
B cells (antibodies, bone marrow) and T cells (thymus; helper and killer) form adaptive immunity against pathogens.
Remember
B and T cells = adaptive defence against pathogens.
Common mistakes
- Linking lymphocytes mainly to allergies; allergies are a malfunction, not their purpose.
- Thinking T cells suppress immunity; only a small regulatory subset damps responses.
- Forgetting T cells mature in the thymus, hence the 'T'.
Exam tip
B = Bone marrow, antibodies. T = Thymus, killing and helping.
Sources
- NCERT Class XII — Biology, Ch 8 (Human Health and Disease: Immunity)
- Kenneth Murphy and Casey Weaver — Janeway's Immunobiology (Garland Science)