What are the components of hemoglobin?

Hemoglobin is the protein that transports oxygen (O2) in human blood from the lungs to the tissues of the body. A hemoglobin molecule is composed of four polypeptide globin chains. Each contains a heme moiety which has an organic part (a protoporphyrin ring made up of four pyrrole rings) and a central iron ion in the ferrous state (Fe2+).

Heme synthesis occurs both in cytosol and in mitochondria of erythrocytes. Protoporphyrin is synthesized from the condensation of glycine and succinyl coenzyme A, eight molecules of each being required to form a linear tetrapyr-role molecule, which finally cyclizes into the protoporphyrin ring. The protoporphyrin then binds to a Fe2+ ion to form heme.

Each heme group contains an iron atom that is able to bind to one oxygen (O2) molecule. Because hemoglobin contains four heme groups, each hemoglobin protein can bind four oxygen molecules.

Fe2+ is a major component of hemoglobin that carries oxygen to all parts of the body. Fe2+ also has a critical role within cells assisting in oxygen utilization, enzymatic systems, especially for neural development, and overall cell function everywhere in the body.
What are the components of hemoglobin?

What are the components of blood?

The total blood volume in an adult is about 5.5 liters. The blood consists of a fluid and formed elements.

Formed elements include:
Red blood cells
White blood cells
Platelets

Of the total volume in the human body, 50% - 60% is plasma or the liquid portion of the blood.

Various components of blood each play a role.  In humans, blood cells are produced by stem cells in the bone marrow.

Plasma is a protein-rich solution. It is the fluid portion of the blood in which electrolytes, nutrients, metabolites, vitamins, hormones, gases and parties are dissolved.

Red blood cells or erythrocytes transport O2 and play an important role in pH regulation. The cells deliver hemoglobin, which is the iron-bearing protein that makes the transportation of oxygen possible.

Hemoglobin also gives human blood and that of many other animals, its red color. The red blood cells normally make-up 40%-50% of the total blood volume.

White blood cells can be divided into neutrophilic, eosinophilic, and basophilic granulocytes, monocytes and lymphocytes.

Neutrophils play a role nonspecific immune defense, whereas monocytes and lymphocytes participate in specific immune response.

Eosinophil is an important defense against parasitic infections. It will increase in allergic states such as hay fever, asthma.

Platelets are needed for hemostasis. Platelets or thrombocytes are cell fragments without nuclei that work with blood clotting chemicals at the site of wounds.

The research has shown that platelets help fight infections by releasing proteins that kill invading bacteria and some other microorganisms.
What are the components of blood?