Final answer:
Hemoglobin is a protein found in red blood cells that consists of alpha and beta globin chains, each bound to a heme group with iron, essential for binding oxygen. The correct option is a.
Step-by-step explanation:
Hemoglobin is a critical component of red blood cells and it plays a vital role in transporting gases such as oxygen and carbon dioxide in the blood. The protein subunits found in hemoglobin are alpha and beta globin chains. In each molecule of hemoglobin, there are four protein subunits: two 'alpha' chains and two 'beta' chains. Each chain is associated with a heme group, containing an iron ion (Fe2+), which is essential for oxygen binding and release.
When oxygen binds to the heme's iron ion, the shape of the hemoglobin molecule changes, allowing it to carry oxygen efficiently. The binding and release of oxygen by hemoglobin are influenced by numerous factors, including the partial pressure of oxygen, pH levels, and the presence of other molecules like carbon dioxide.
Changes in the body, such as disease states, can affect hemoglobin's capacity to carry oxygen, which is why understanding the structure and function of hemoglobin is crucial in medicine. In summary, the two types of protein chains in hemoglobin that enable its oxygen-carrying function are the alpha and beta subunits.