9.
Human red blood cells (RBCs) cannot be grown in cultures because
a. RBCs require a steady oxygen supply
b. RBCs are extremely fragile
c. RBCs are terminally differentiated cells
d. RBCs are biconcave
Human red blood cells (RBCs) cannot be grown in cultures primarily because they are terminally differentiated cells that lack a nucleus and cannot divide or proliferate.
Option Analysis
a. RBCs require a steady oxygen supply: Mature RBCs transport oxygen but can be maintained short-term in hypoxic or controlled culture conditions without proliferation; this does not prevent culturing.
b. RBCs are extremely fragile: While RBCs have delicate membranes, fragility affects handling more than long-term growth, and other fragile cells like neurons are cultured successfully.
c. RBCs are terminally differentiated cells: Correct. Mature RBCs lose their nucleus during erythropoiesis, exiting the cell cycle permanently and lacking machinery for DNA replication or division needed for culture expansion.
d. RBCs are biconcave: This shape aids flexibility and gas exchange in vivo but is irrelevant to proliferation capability in culture.
Human red blood cells (RBCs) cannot be grown in cultures because they represent the end stage of erythropoiesis, a process where precursor cells progressively specialize into oxygen-carrying machines incapable of self-renewal. This fundamental limitation arises from terminal differentiation, making option c the precise answer for competitive exams like CSIR NET Life Sciences.
Core Reason: Terminal Differentiation
Mature RBCs eject their nucleus and organelles during reticulocyte maturation, halting cell division permanently as they prioritize hemoglobin packaging over replication. Without DNA synthesis capacity, they cannot proliferate in vitro, unlike stem cell-derived precursors used in experimental RBC production.
Why Other Options Fail
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Steady oxygen supply supports short-term viability but not growth.
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Fragility poses handling issues, not a barrier to culturing similar cells.
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Biconcave shape enhances function in blood, irrelevant to division.
Exam Relevance
For CSIR NET aspirants, recognize terminal differentiation as the key concept linking cell biology and hematopoiesis—RBCs are replaced daily by bone marrow progenitors, not cultured expansion.
