Final answer:
The question addresses the composition of different types of hemoglobin in humans. Hemoglobin types include HbA with α2β2 chains, HbA2 with α2δ2 chains, and HbF with α2β2 chains. Abnormal hemoglobins can arise due to genetic mutations.
Step-by-step explanation:
The question concerns hemoglobin types and their composition in humans. Hemoglobin (Hb) is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. Various forms of hemoglobin exist, each composed of different globin chains. Adult hemoglobin (HbA) consists of two alpha (α2) and two beta (β2) chains.
Minor adult hemoglobin (HbA2), which is considered normal in some human beings, consists of two alpha (α2) and two delta (δ2) chains. \Fetal hemoglobin (HbF), found in the growing fetus, contains two alpha (α2) and two gamma (β2) chains.
There can be abnormal hemoglobins due to mutations in the genes responsible for hemoglobin synthesis, leading to defective alpha or beta chains. For instance, in sickle cell hemoglobin (HbS), a defect in the beta chain causes glutamic acid at the 6th position to be replaced by valine, which can lead to various health issues.