Final answer:
The prosthetic group of hemoglobin and myoglobin is heme, its organic ring component is porphyrin, and the central atom is iron in the Fe²+ state, which is crucial for oxygen binding and transport.
Step-by-step explanation:
Complete the sentences about heme. Some terms will not be used. The prosthetic group of hemoglobin and myoglobin is heme. The organic ring component of heme is porphyrin. Under normal conditions, the central atom of heme is iron in the Fe²+ state. When oxygen binds to iron, it causes a shift in the three-dimensional structure of hemoglobin, illustrating how oxygen transport is facilitated by these biochemical components.
Heme is critical in the biology of respiring organisms because it allows for the transport of oxygen throughout the body. Myoglobin and hemoglobin are two well-known proteins that contain heme, and they are found in the muscle tissue and red blood cells, respectively. Hemoglobin's structure is intricate; it is composed of four polypeptide chains—two alpha and two beta—and each chain holds one heme group. These heme groups are responsible for the oxygen binding capacity of hemoglobin. The iron atom in heme exists in a low oxidation state (Fe²+), which is essential for oxygen binding; oxidation to Fe³+ inactivates the iron's oxygen-binding capability.