NEET BIOLOGY

Detailed explanation-1: -Mammalian RBC are biconcave, circular, non nucleated. The cytoplasm of erythrocytes is rich in hemoglobin, an iron-containing biomolecule, that can bind oxygen and is responsible for the red color of the cells.

Detailed explanation-2: -All healthy mammalian RBCs are disc-shaped (discocyte) when not subjected to external stress.

Detailed explanation-3: -RBCs are biconcave disc-shaped which maximises the cell membrane for the diffusion of oxygen. The shape also helps in easy movement of cells through the blood vessels. RBCs are enucleated i.e. they lack nucleus so that a large amount of haemoglobin can be accommodated in it.

Detailed explanation-4: -The shape of the human red blood cell is known to be a biconcave disk. It is evident from a variety of theoretical work that known physical properties of the membrane, such as its bending energy and elasticity, can explain the red-blood-cell biconcave shape as well as other shapes that red blood cells assume.

Detailed explanation-5: -The shape of RBC’s varies in different vertebrates. In mammals, these are normally circular, biconcave and enucleated but there is an exception in camels, where they are oval in shape, biconcave (which gives flexibility and quick diffusion of gases) and nucleated. Hence, option A is correct.