Question

Regarding human haemoglobin, which of the following statements is true?

• A. When the immunoglobin and haemoglobin and globin fractions are separated, the haem group can bind oxygen reversibly.
• B. Different haemoglobins contain an identical haeme group but differ in the character of the globin fraction.
• C. The haemoglobin of adult humans consists of four identical subunits and a single haem group.
• D. All the haemoglobin molecules in any one species are identiical.

Answer 1

Answer: (B)

Different haemoglobins contain an identical haeme group but differ in the character of the globin fraction.

Haemoglobin is an oxygen-carrying molecule present in the blood. Haemoglobin is made up of four protein subunit (globin) and haeme group. Adult haemoglobin is made up of 2 alpha and 2 beta subunits. However, in very less adults, 2 alpha and 2 delta subunits are present in haemoglobin. Foetal haemoglobin is made up of 2 alpha and 2 gamma subunits. Hence, all the haemoglobin molecules in any one species are not always identical. In haemoglobin, haeme group binds oxygen irreversibly as haeme group also binds to carbon dioxide.

Thus, the correct answer is option B.