Biology · BIOMOLECULES

Adult human haemoglobin (Hb) exhibits a quaternary protein architecture. Which of the following statements correctly describes its subunit composition?

1. A
   It consists of 2 identical polypeptide chains of \( \alpha \) type.
2. B
   It consists of 4 identical polypeptide subunits of \( \beta \) type.
3. C
   It consists of 4 subunits: two subunits of \( \alpha \) type and two subunits of \( \beta \) type.
4. D
   It consists of 3 subunits: two \( \alpha \) subunits and one \( \beta \) subunit.