Haemoglobin is a protein inside red blood cells and it carries which of the following?

Correct option is A

The correct answer is (a) Oxygen

Explanation:

• Haemoglobin (Hb) is a complex iron-rich protein found in the red blood cells (erythrocytes) of almost all vertebrates.

• Its primary function is to bind with oxygen molecules in the lungs and transport them to the body's tissues and organs.

• Each haemoglobin molecule contains four iron atoms, allowing it to carry up to four molecules of oxygen.

• When haemoglobin binds with oxygen, it forms a bright red compound called oxyhaemoglobin.

• According to NCERT Class 11 Biology, the binding of oxygen with haemoglobin is primarily related to the partial pressure of $O_2$ and $CO_2$.

Information Booster:

• Haemoglobin also plays a minor role in transporting carbon dioxide back from the tissues to the lungs (as carbamino-haemoglobin), though most $CO_2$ is transported as bicarbonate ions in the plasma.

• A deficiency of haemoglobin in the blood leads to a condition called anemia, which results in reduced oxygen-carrying capacity and fatigue.

Additional Knowledge:

Carbon dioxide (Option b)

• While haemoglobin does carry about 20-25% of the body's carbon dioxide, its defining and primary biological role is the transport of oxygen.

• The majority of $CO_2$ is actually carried dissolved in the blood plasma as bicarbonate.

Nitrogen (Option c)

• Nitrogen is the most abundant gas in the atmosphere, but it is inert in the human respiratory process.

• It dissolves in the blood according to pressure (Henry's Law) but is not actively carried by haemoglobin for cellular metabolism.

Ozone (Option d)

• Ozone ($O_3$) is a toxic gas if inhaled directly into the lungs and is not a part of the normal respiratory exchange.

• It is primarily known for its role in the Earth's upper atmosphere, protecting the planet from UV radiation.