Question

Arrange the sequence of erythroid series. A. Basophilic erythroblast
B. Polychromatic erythroblast
C. Reticulocyte
D. Proerythroblast
E. Orthochromatic erythroblast

• A. D, A, B, E, C
• B. D, B, A, C, E
• C. D, A, B, C, E
• D. D, A, E, B, C

Hint:

An easy mnemonic: “Pro-BPO-R” → Proerythroblast, Basophilic, Polychromatic, Orthochromatic, Reticulocyte.

Answer 1

The Correct Option is A

Step 1: Recall the erythropoiesis stages.
Erythropoiesis is the process by which red blood cells (RBCs) are produced in the bone marrow. The process begins with a large immature cell (proerythroblast) and ends with a mature RBC.
Step 2: First stage – Proerythroblast.
The proerythroblast is the earliest recognizable precursor in the erythroid series. It is large, with a large nucleus and basophilic cytoplasm.
Step 3: Second stage – Basophilic erythroblast.
This cell is smaller than the proerythroblast and has strongly basophilic cytoplasm due to abundant ribosomes.
Step 4: Third stage – Polychromatic erythroblast.
At this stage, the cytoplasm begins to show mixed staining (blue + pink), due to decreasing ribosomes and increasing hemoglobin.
Step 5: Fourth stage – Orthochromatic erythroblast.
This cell is almost filled with hemoglobin, and the nucleus becomes pyknotic and eventually extruded.
Step 6: Fifth stage – Reticulocyte.
After enucleation, the cell becomes a reticulocyte, which still contains some ribosomal RNA. Reticulocytes mature into RBCs in circulation.
Step 7: Conclusion.
Thus, the correct sequence is: Proerythroblast → Basophilic erythroblast → Polychromatic erythroblast → Orthochromatic erythroblast → Reticulocyte.
Final Answer:
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