Final answer:
The unique biconcave shape of red blood cells is maintained by a protein called spectrin, which is anchored to their membrane. This shape is essential for optimal gas exchange and the cells' ability to navigate through narrow blood vessels.
Step-by-step explanation:
Red blood cells, also known as erythrocytes, have a distinctive biconcave shape that is crucial for their function in transporting oxygen and carbon dioxide. This biconcave form allows for a higher surface area relative to the volume of the cell, which is optimal for gas exchange. Moreover, it grants the ability to deform when passing through narrow capillaries, ensuring efficient circulation through the body's vast network of blood vessels. The structure and flexibility of red blood cells are maintained by internal proteins called spectrin, which are part of the cytoskeleton and are attached to the inner face of the membrane. Spectrin proteins are essential for the cell's durability and shape retention, allowing it to recover its biconcave form after distortion during circulation.