Question

Oxygen is transported through blood mainly by
A. Leukocytes.
B. Erythrocytes.
C. Thrombocytes.
D. Blood plasma.

Answer 1

Hint: Respiration is a physiological process that occurs in living organisms. The exchange of oxygen and carbon dioxide between the external atmosphere and the blood is performed by specialized blood cells that contain haemoglobin.

Complete answer: The role of erythrocytes, also called red blood cells (RBCs), is to transport oxygen into the blood. For this feature, the form of erythrocytes is ideal. Erythrocytes tend to be circular, viewed from the top, but a side view reveals that they are actually biconcave discs. This form improves the cell's surface-area-to-volume ratio, thus enhancing the efficiency of oxygen and carbon dioxide diffusion into and out of the cell. There is also a versatile plasma membrane in erythrocytes. The plasma membrane helps erythrocytes to squeeze through capillaries as small as \[3\text{ }mm\] across, which have a diameter of \[7\text{ }mm\]. Erythrocytes contain massive quantities of oxygen-binding haemoglobin, which is a protein. Erythrocytes lose their nucleus and other organelles when they form in the bone marrow, in order to make room for more haemoglobin to hold more oxygen. \[{{O}_{2}}\] transport does not include leukocytes (involved in immune response), thrombocytes (involved in blood clotting) and blood plasma. Thus, Oxygen is mainly transported by erythrocytes via the blood. These cells contain a metalloprotein called haemoglobin, which has a ring-like shape and is composed of four subunits. There is one atom of iron bound to a molecule of heme in each subunit.
Hence, the correct answer is option B.

Note: In the form of oxyhaemoglobin, about \[97%\] of oxygen is transported. 63 percent of carbon dioxide is shipped in the form of bicarbonates. As carbamino compounds, 30 percent of carbon dioxide is brought along.