Final answer:
The yellow color of plasma is mainly due to the presence of bilirubin, a pigment that results from the breakdown of hemoglobin from red blood cells.
Step-by-step explanation:
The yellow color of plasma results mainly from the presence of bilirubin, which is a breakdown pigment formed from the destruction of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen. When red blood cells are broken down, bilirubin is produced and imparts the plasma with a yellowish hue. This process is part of the normal life cycle of erythrocytes (red blood cells). Furthermore, in conditions like jaundice, where bilirubin is not effectively removed due to liver dysfunction, the yellow color can become more pronounced.
Plasma, which comprises about 90% water, also contains dissolved proteins, glucose, ions, hormones, and gases. These components are essential for various physiological processes throughout the body. However, it is bilirubin that predominantly gives plasma its characteristic color.