Question

Adult human RBCs are enucleated. Which of the following statement(s) is/are most appropriate explanation for this feature ? (a) They do not need to reproduce (b) They are somatic cells (c) They do not metabolize (d) All their internal space is available for oxygen

• A. only (a)
• B. (a), (c) and (d)
• C. (b) and (c)
• D. only (d)

Answer 1

The Correct Option is B

The question is about why adult human Red Blood Cells (RBCs) are enucleated, meaning they lack a nucleus. The correct answer provided is options (a), (c), and (d). Let's examine each statement to understand why these options are correct and why others are incorrect:

1. Statement (a): They do not need to reproduce
   • This statement is correct. RBCs have a primary function of transporting oxygen rather than reproducing. They have a limited lifespan (about 120 days) and do not need to divide or proliferate. Instead, new RBCs are constantly produced in the bone marrow.
2. Statement (b): They are somatic cells
   • This statement is misleading. While RBCs are indeed somatic cells, this isn't a reason for them being enucleated. There are various other somatic cells that do have nuclei. The term ‘somatic cells’ refers to all body cells except germ cells, and enucleation is not a necessity for a cell to be somatic.
3. Statement (c): They do not metabolize
   • This is partially correct. RBCs have a very limited ability to metabolize. They primarily produce ATP through glycolysis and do not engage in extensive metabolic activities that require a nucleus. This adaptation helps prioritize their role in oxygen transport.
4. Statement (d): All their internal space is available for oxygen
   • This statement is correct. The absence of a nucleus (and other organelles) allows more space for hemoglobin molecules, which bind and transport oxygen. This adaptation maximizes oxygen-carrying capacity.

Given these analyses, the most appropriate and correct explanation for why RBCs are enucleated involves options (a), (c), and (d). These options together explain the functional adaptations of RBCs to maximize their efficiency in oxygen transport.