Question

Assertion (A): Haemopoitic stem cells are multipotent cells.
Reason (R): They can produce different types of related cells, namely, blood cells.

• A. Both (A) and (R) are true. (R) is correct explanation for (A)
• B. Both (A) and (R) are true. (R) is not correct explanation for (A)
• C. (A) is true. But (R) is false
• D. (A) is false. But (R) is true

Hint:

Remember potency hierarchy:
Zygote = Totipotent
Embryonic stem cells = Pluripotent
Hematopoietic/Adult stem cells = Multipotent

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question asks us to analyze the assertion regarding the multipotency of hematopoietic stem cells and the reasoning behind their functional differentiation into blood cell types.

Step 2: Key Concept and Approach:
Stem cells are classified based on their differentiation potency:
- Totipotent: can form all cell types.
- Pluripotent: can form all germ layer cells.
- Multipotent: can differentiate into multiple, closely-related cell types belonging to a specific lineage.

Step 3: Detailed Explanation:

• Multipotent Nature: Assertion (A) is true.
Hematopoietic stem cells (HSCs) found in bone marrow are classic examples of multipotent stem cells because they are committed to a specific lineage.

• Differentiation Spectrum: Reason (R) is true.
These cells differentiate specifically into various blood cells, including erythrocytes, leukocytes (neutrophils, lymphocytes, monocytes, eosinophils, basophils), and platelets.
They cannot form cells of unrelated tissues like muscle or nerve cells.

• Causal Link: Because their differentiation is restricted to a group of closely-related cells (namely, blood cells), they are classified as multipotent.
Hence, Reason (R) is the direct explanation for Assertion (A).


Step 4: Final Answer:
Both (A) and (R) are true, and (R) is the correct explanation for (A).