Question

The correct statement in respect of protein haemoglobin is that it
A. Functions as a catalyst for biological reactions
B. Maintains blood sugar level
C. Act as an oxygen carrier in the blood
D. Forms antibodies and offers resistance to diseases

Answer 1

Hint: To solve this question we have to know about haemoglobin. Protein is a naturally occurring and extremely complex substance that consists of amino acid residues. haemoglobin is a type of protein present in the blood of all red blood living organisms.

Complete Step by Step Answer:
haemoglobin is the major constituent of our blood. haemoglobin contains the heme unit. It contains the only metal atom iron. In haemoglobin the iron atom exists in $+2$ oxidation state. haemoglobin contains a porphyrin ring where the iron atom is connected with the porphyrin ring through nitrogen atoms of the porphyrin ring.

Oxygen can combine with haemoglobin in a bent fashion and is called oxy haemoglobin and increases the oxidation state of iron to $+3$. The combination of oxygen makes haemoglobin pure and supplies the oxygen to our blood. Thus haemoglobin majorly acts as an oxygen supplier in blood.
Thus the correct option is C.

Note: Haemoglobin is essential for oxygen transport in our blood. The iron atom remains in $+2$ oxidation state and exists as high spin iron. When iron connects with oxygen atoms in a bent fashion the oxidation state of iron changes to $+3$ and iron becomes low spin.