Question

Iron-containing haeme is attached with globin of haemoglobin as
A. Coenzyme
B. Apoenzyme
C. Prosthetic group
D. Inorganic group

Answer 1

Hint: The red colour of the blood is imparted by a certain compound which has a metal group attached to it. It has a complex structure. It forms an irreversible bond with the oxygen. Deficiency of it can cause anaemia.

Complete answer:
Haemoglobin is the red coloured giving component in the blood. Haem is the Fe (iron) in the haemoglobin. Haemoglobin is responsible for binding to the oxygen to be transported in the bloodstream.
It has four subunits, each subunit having an iron molecule. Each iron will bind to one oxygen molecule.

> Option A: Coenzyme: It is the organic compound which is non- proteinaceous that binds to the enzyme to proceed a reaction. They are the co-factors but cannot function alone.

> Option B: Apoenzyme: These are the inactive enzymes. They gets activated when bonded to the organic or inorganic cofactors.

> Option C: Prosthetic group: Fe, Mg, Co etc. work as prosthetic groups as they are the non-proteinaceous groups essential for the working of the biological proteins. These metal ions are the prosthetic groups.

> Option D: Inorganic group: these groups that lack carbon-hydrogen bonds are the inorganic groups.

Hence, the correct answer is option (C).

Note: Each RBC has about 250 million Hb molecules. An average adult has about 5 litres of blood. Its deficiency majorly iron can cause anaemia. Oxyhemoglobin is when oxygen is attached to the haemoglobin compound. It is a globular protein with 4 iron atoms at its corners. Max Perutz and John Kendrew discovered the structure.