What component of blood contains iron and carries oxygen?

Haemoglobin is the component of blood that contains iron and is responsible for carrying oxygen. It is a protein found in red blood cells and plays a critical role in transporting oxygen from the lungs to various tissues throughout the body. The iron in haemoglobin binds to oxygen molecules, allowing for efficient oxygen transport. This is essential for cellular respiration, where oxygen is used to produce energy within cells.

Plasma, which is the liquid portion of blood, primarily consists of water, electrolytes, proteins (other than haemoglobin), hormones, and waste products. While plasma serves important functions, it does not contain iron or carry oxygen. Platelets are small cell fragments involved in blood clotting, and they do not carry oxygen. Serum is the liquid that remains after blood has clotted and is essentially plasma without the clotting factors; it also does not carry oxygen or contain haemoglobin.

Haemoglobin's unique structure allows it to carry the maximum amount of oxygen, and its ability to release oxygen in tissues makes it vital for sustaining life. This understanding highlights the importance of haemoglobin in both nutrition and physiological processes.