Final answer:
Adult hemoglobin (HbA) consists of two alpha chains and two beta chains. There are also other forms of hemoglobin like HbF with gamma chains and HbA2 with delta chains.
Step-by-step explanation:
Hemoglobin is a complex protein found in red blood cells, crucial for transporting oxygen throughout the body. This important molecule has a quaternary structure consisting of four polypeptide chains. Specifically, adult hemoglobin (HbA) is composed of two alpha (α) chains and two beta (β) chains. Thus, along with the two alpha chains, hemoglobin is composed of two beta chains. The beta chains, like the alpha chains, are vital for the protein's ability to bind oxygen.Other forms of hemoglobin exist, such as fetal hemoglobin (HbF), which comprises two alpha and two gamma (γ) chains, and a minor adult form known as HbA2, containing two alpha and two delta (δ) chains. Understanding the structure of hemoglobin is key in studies of its function and its role in various diseases.