UPSC Prelims 2012 Q16: Science & Technology – Biotechnology & Genetics
With reference to 'stem cells', frequently in the news, which of the following statements
is/are correct?
1. Stem cells can be derived from mammals only.
2. Stem cells can be used for screening new drugs.
3. Stem cells can be used for medical therapies.
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 3 only
- (d) 1, 2 and 3
Answer: (b) 2 and 3 only
Explanation
Stem cells
Stem cells are unspecialised cells that can divide and turn into many kinds of cell.
| Statement | Verdict | Fact |
|---|---|---|
| 1. Stem cells can be derived from mammals only | Incorrect | All multicellular animals have them, and plants have them in their meristems |
| 2. Stem cells can be used for screening new drugs | Correct | New medicines are tested on cells grown from stem cells |
| 3. Stem cells can be used for medical therapies | Correct | Bone marrow transplant for blood cancers is the best example |
Types of stem cells:
| Type | Source | Power |
|---|---|---|
| Embryonic | Early embryo | Pluripotent: can form almost any cell |
| Adult | Bone marrow, cord blood, fat | Multipotent: limited range |
| Induced pluripotent (iPS) | Adult cells reprogrammed in the laboratory | Pluripotent; Nobel Prize 2012 (Yamanaka) |
Answer: (b) 2 and 3 only.
Why each option is right or wrong
- (a) Incorrect. Statement 1 is false; stem cells are not limited to mammals.
- (b) CORRECT. Stem cells are used for screening drugs and for medical therapies.
- (c) Incorrect. Statement 2 is also true.
- (d) Incorrect. Statement 1 is false.
Key point
Stem cells: unspecialised, self-renewing; found in animals and plants; embryonic (pluripotent), adult (multipotent), iPS (Nobel 2012); used in therapy and drug testing.
Remember
Stem cells: therapy + drug screening; not mammals only.
Common mistakes
- Accepting 'mammals only'; the word 'only' is the trap.
- Forgetting that plants have stem cells in meristems.
- Confusing pluripotent and multipotent cells.
Exam tip
'Only' is the tell. Stem cells exist across living things.
Sources
- Indian Council of Medical Research — National Guidelines for Stem Cell Research (2017)
- Nobel Prize — The Nobel Prize in Physiology or Medicine 2012