Final answer:
The β-globin locus spans approximately 50-60 kBs and contains genes coding for globin proteins that form the protein portion of hemoglobin, each capable of binding to heme and carrying oxygen in the blood.
Step-by-step explanation:
The β-globin locus is a cluster of genes that spans approximately 50-60 kilobases (kBs). This region contains several genes that encode for the globin protein subunits of hemoglobin. Each gene within the locus codes for a protein that can form the globin portion of hemoglobin, which consists of four globin proteins, each bound to a molecule of heme. Hemoglobin is a critical component for oxygen transport in the blood as it can carry up to 120 molecules of oxygen. The globin protein itself is made up of four polypeptide chains, two alpha (α) chains containing 141 amino acids each and two beta (β) chains with 146 amino acids each. The molecular weight of hemoglobin is 65,000. All four of these chains contain a specific pocket-like area where the heme group is located, which includes an iron center essential for binding to oxygen.