Question

On average, the number of oxygen molecules bound to heme groups in hemoglobin in venous blood is __________.

a) 1
b) 2
c) 3
d) 4

Answer 1

The average number of oxygen molecules bound to heme groups in hemoglobin in venous blood is 4, with each hemoglobin molecule capable of carrying up to four oxygen molecules.

Step-by-step explanation:

On average, the number of oxygen molecules bound to heme groups in hemoglobin in venous blood is 4. This is because each hemoglobin molecule consists of four globin proteins, each bound to a molecule of heme, which in turn can bind one oxygen molecule. Hence, each hemoglobin can carry up to four oxygen molecules. A single erythrocyte (red blood cell) contains about 300 million hemoglobin molecules, which means it can transport up to 1.2 billion oxygen molecules when fully saturated with oxygen.