Which protein in red blood cells is responsible for carrying oxygen?

Hemoglobin is the key protein in red blood cells that carries oxygen throughout the body. This protein is composed of four subunits, each containing a heme group that can bind to oxygen molecules. When blood passes through the lungs, hemoglobin picks up oxygen, which it then transports to tissues and organs that need it for metabolic processes.

The structure of hemoglobin is crucial for its function; its ability to change shape upon binding to oxygen allows it to load oxygen in the oxygen-rich environment of the lungs and release it in oxygen-poor areas. This efficiency supports the body's overall oxygen transport needs.

Myoglobin, although involved in oxygen binding, is primarily found in muscle tissues rather than in red blood cells, where it serves to store oxygen rather than transport it. Albumin and globulin are proteins found in blood plasma, but they serve different roles, such as maintaining osmotic pressure and immune functions, rather than oxygen transport.