Question

How is oxygen and carbon dioxide transported in human beings?

Answer 1

Transport of Oxygen:
Haemoglobin transports oxygen molecule to all the cells in the body for cellular respiration. The haemoglobin pigment present in the blood binds to ${\text{O}}_2$ molecules that are obtained from breathing and thus forms oxyhaemoglobin. This oxygenated blood is then distributed to all the cells of the body by the heart. After giving away ${\text{O}}_2$ to the body cells, blood takes away ${\text{CO}}_2$ which is the end product of cellular respiration and the blood becomes de-oxygenated.

Transport of carbon dioxide:
Since haemoglobin pigment has less affinity for ${\text{CO}}_2$, ${\text{CO}}_2$ is mainly transported in the dissolved form. The deoxygenated blood gives ${\text{CO}}_2$ to lung alveoli and takes ${\text{O}}_2$ in return.