Kaplan Nursing Entrance Practice Exam

Why can red blood cells not repair themselves?

1. They lack oxygen to energize the repair

2. They do not have a nucleus

3. They lose nutrients rapidly

4. They are too small to perform repairs

The correct answer is: They do not have a nucleus

Red blood cells, or erythrocytes, cannot repair themselves primarily because they do not possess a nucleus. The absence of a nucleus means that red blood cells lack the necessary genetic material and cellular machinery to carry out processes like protein synthesis, which are crucial for cellular repair and regeneration. Typically, cells rely on their nucleus to direct repair mechanisms, produce essential proteins, and control various functions. Without a nucleus, red blood cells cannot produce new hemoglobin or other components needed for their repair. This limitation makes them highly specialized for their role in oxygen transport but unable to respond to damage or distress in the same way that other cells can. Red blood cells are primarily designed to efficiently carry oxygen from the lungs to tissues and return carbon dioxide for exhalation, which is why they sacrifice the ability to self-repair. The other factors mentioned, such as the lack of oxygen for energizing repairs, rapid nutrient loss, or being too small, do not accurately describe the fundamental reason for the inability to repair; these factors do not directly impact a cell's capability for self-repair in the context of red blood cells. The key reason lies in their lack of a nucleus, which is central to the cell's functionality and ability to respond to damage.