Final answer:
Normal adult hemoglobin, HbA, is composed of α2β2, consisting of two alpha and two beta chains. It is essential in oxygen transport within the bloodstream.
Step-by-step explanation:
The composition of normal adult hemoglobin, commonly referred to as HbA, is α2β2, indicating that it is comprised of two alpha (α) chains and two beta (β) chains. This is option 1 from the choices provided. Each of these globin molecules is attached to a heme group, which contains an iron ion, playing a critical role in oxygen transport within the bloodstream.
There are variations of hemoglobin, such as HbA2 and HbF, which also consist of different combinations of globin chains. HbA2 is composed of two alpha and two delta (δ) chains, whereas HbF, the fetal form of hemoglobin, is made up of two alpha and two gamma (γ) chains.
Hemoglobin is a protein composed of four folded chains, consisting of two alpha (α) chains and two beta (β) chains. This composition is written as α2β2. Therefore, the composition of HbA, which is a type of normal hemoglobin found in adult human beings, is α2β2.
Therefore answer is 1) α2β2.