Question

The inner cell mass present in the blastocyst of a mammalian embryo is

• A. Totipotent
• B. Pluripotent
• C. Multipotent
• D. Unipotent

Hint:

Stem Cell Potency:
Totipotent = Zygote/Morula (Embryonic + Extraembryonic/Placenta).
Pluripotent = Inner Cell Mass ESCs (All 3 germ layers).
Multipotent = Adult stem cells (Lineage-restricted).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Stem cell developmental potency hierarchy: totipotent zygote $ ightarrow$ pluripotent inner cell mass $ ightarrow$ multipotent germ line progenitors $ ightarrow$ unipotent somatic cells.

Step 2: Detailed Explanation:
Cell potency classifications:
1. Totipotent: The zygote and blastomeres up to the 8-cell morula stage; can give rise to all embryonic tissues plus all extraembryonic trophoblast/placental tissues.
2. Pluripotent: The Inner Cell Mass (ICM Embryoblast) of the blastocyst; can differentiate into all cell lineages of the three embryonic germ layers (ectoderm, mesoderm, and endoderm) as well as the germline, but cannot form the extraembryonic trophectoderm/placenta.
3. Multipotent: Adult tissue stem cells (e.g., hematopoietic stem cells).

Step 3: Final Answer:
Hence, the inner cell mass of a blastocyst is Pluripotent, matching option (B).