How many oxygen molecules are on a hemoglobin?
Hemoglobin has an oxygen-binding capacity of 1.34 mL O2 per gram, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.
The heme group contains one iron atom, and this can bind one molecule of oxygen. Because each molecule of hemoglobin contains four globins, it can carry up to four molecules of oxygen.
- about 120 days
- Thus, each hemoglobin can carry 4 O2's. One RBC contains 250 million Hb molecules (ie. 1 RBC can carry as many as 1 billion molecules of O2). Fetal Hb (humans & cattle) has gamma instead of beta globins.
- The process by which hemoglobin binds oxygen to form oxyhemoglobin is called loading. That's what happens in the lungs. Once in the metabolizing tissues, oxyhemoglobin is unloaded as oxygen is released and diffuses into the plasma and ultimately our cells.
It is the iron atom that binds oxygen as the blood travels between the lungs and the tissues. There are four iron atoms in each molecule of hemoglobin, which accordingly can bind four atoms of oxygen. Globin consists of two linked pairs of polypeptide chains.
- The name hemoglobin is derived from the words heme and globin, reflecting the fact that each subunit of hemoglobin is a globular protein with an embedded heme group. Each heme group contains one iron atom, that can bind one oxygen molecule through ion-induced dipole forces.
- Hemoglobin (Hbg) measures the amount of the hemoglobin molecule in a volume of blood and normally is 13.8 to 17.2 grams per deciliter (g/dL) for men and 12.1 to 15.1 g/dL for women.
- High hemoglobin count occurs less commonly because: Your red blood cell production increases to compensate for chronically low blood oxygen levels due to poor heart or lung function. You have a bone marrow dysfunction that results in increased production of red blood cells.
Each human red blood cell contains approximately 270 million of hemoglobin molecules. Each hemoglobin molecule carries four heme groups; hemoglobin comprises about a third of the total cell volume.
- Women who are pregnant commonly have low hemoglobin counts. A low hemoglobin level count is generally defined as less than 13.5 grams of hemoglobin per deciliter (135 grams per liter) of blood for men and less than 12 grams per deciliter (120 grams per liter) for women.
- White blood cells called macrophages destroy germs as soon as they detect them. However, if a viral infection begins to take hold we fight back using a more powerful defence of white cells called T and B lymphocytes. Antibodies are a special protein made by B cells.
- about 120 days
Updated: 3rd December 2019