Question

Oxyhemoglobin is an unstable substance and breaks down easily to oxygen and haemoglobin. Because of its instability, oxyhaemoglobin

• A. Can carry extra oxygen
• B. Readily picks up oxygen from the lungs
• C. Readily gives up oxygen to body cells
• D. Is quickly broken down in the liver

Answer 1

The correct option is C Readily gives up oxygen to body cells

In direct diffusion and tracheal systems, oxygen and carbon dioxide move back and forth directly between cells and the surrounding environment. In other systems, some mechanism is needed to carry these gases between cells and the outside environment. In animals with lungs or gills, oxygen is absorbed by the bloodstream, converted into an unstable (easily broken down) chemical compound, and then carried to cells. When the compound reaches a cell, it breaks down and releases the oxygen. The oxygen then passes into the cell. In the reverse process, carbon dioxide is released from a cell into the bloodstream. There the carbon dioxide is used to form another unstable chemical compound, which is carried by the bloodstream back to the gills or lungs. At the end of this journey, the compound breaks down and releases the carbon dioxide to the surrounding environment. Various animals use different substances to form these unstable compounds. In humans, for example, the substance is a compound known as hemoglobin. In the lungs, hemoglobin reacts with oxygen to form oxyhemoglobin. Oxyhemoglobin travels through the bloodstream to cells, where it breaks down to form hemoglobin and oxygen. The oxygen then passes into cells. So, oxyhemoglobin is unstable because, it readily gives up oxygen to body cells. Therefore, the correct answer is option C.