Adult hemoglobin is composed of which subunits?

Adult hemoglobin is composed of which subunits?

• A. Four alpha
• B. Two alpha and two gamma
• C. Two alpha and two beta
• D. Four beta

Answer: (C)

Hemoglobin in adults is a tetramer, built from four protein subunits. The common adult form consists of two alpha chains and two beta chains (α2β2), with each chain binding a heme group to carry oxygen. This arrangement is what allows hemoglobin to pick up oxygen in the lungs and release it in tissues throughout the body. A fetal form uses two alpha and two gamma chains (α2γ2), which gives it a higher affinity for oxygen, and after birth the beta chains replace the gamma chains as development shifts to the adult form. So the adult subunit composition is two alpha and two beta.

Hemoglobin in adults is a tetramer, built from four protein subunits. The common adult form consists of two alpha chains and two beta chains (α2β2), with each chain binding a heme group to carry oxygen. This arrangement is what allows hemoglobin to pick up oxygen in the lungs and release it in tissues throughout the body. A fetal form uses two alpha and two gamma chains (α2γ2), which gives it a higher affinity for oxygen, and after birth the beta chains replace the gamma chains as development shifts to the adult form. So the adult subunit composition is two alpha and two beta.