Question

How many haeme molecules are present in one molecule of haemoglobin?

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

Answer: (D)

Haemoglobin is one of a group of globular proteins occurring widely in animals as oxygen carriers in blood. Vertebrate haemoglobin comprises two pairs of polypeptide chains, known as $\alpha$-chains and $\beta$-chains (forming the globin protein) with each chain folded to provide a binding site for a haem group. Each of the four haem groups binds one oxygen molecule to form oxyhaêmoglobin.