What percent of a healthy adult human is whole blood? What is the mass (in grams) of whole blood in a healthy adult human?

A healthy adult that weighs between 150 to 160 pounds would have a mass of approximately 4,982 grams to 5,300 grams of blood. 

Depending on the source that is used, blood accounts for 7%, or one-eleventh, of a healthy adult’s body weight. As an example, if a human weighed between 150 and 160 pounds, his or her volume of blood would be roughly between 4.7 to 5 liters. According to Hypertextbook, whole blood (plasma and its contents) has a density of approximately 1060 kg/m3. When converted, this is the same as 1.06 g/cm3. There is 1000 cm3 per one liter. Therefore, a healthy adult human that has 4.7 to 5 liters of blood would have between 4,982 grams and 5,300 grams of blood.

Blood is important to organisms because oxygen attaches to the hemoglobin inside red blood cells. In this way, red blood cells deliver the oxygen to where it is needed throughout the body. Oxygen is used by the body in a process that is called cellular respiration. During cellular respiration, oxygen and glucose are converted into carbon dioxide gas, water, and an energy source that is called adenosine triphosphate (ATP). Red blood cells also pick up the carbon dioxide that is produced during cellular respiration and brings the gas to the lungs so that it can be eliminated from the body.