Question

20.Diversity and biological functions of blood plasma proteins. (biochemistry)

(please explain with more explanation its my final exam question...thank you ! :))

Answer 1

Answer 20 :

There are 3 Plasma proteins present in the plasma namely - Albumin, Globulin and Fibrinogen. Plasma proteins are very essential for the body carrying out diverse functions :

1. Fibrinogen is essential for coagulation of blood. It is because of this protein, that we do not bleed to death even on minor cuts and wounds. To stop the blood flow Fibrinogen makes a mesh of strands on the cut.
2. Gamma globulins are an important part of body's defense mechanism. They act as antibodies and protect us from foreign antigens, bacteria, etc. The 5 types of immunoglobulins are IgG, IgM, IgA, IgE and IgD.
3. Plasma proteins play essential role for transport of various substances in the blood. Albumin, Alpha and Beta Globulins are responsible for transport of hormones, enzymes, etc. Alpha and Beta globulins also transport inorganic metals in the blood.
4. They play a role in maintaining oncotic pressure. At the capillary level, most of the substances are exchanged between blood and tissues except the plasma proteins. These cannot pass through the capillary membrane because of their large size. In the blood, these proteins exert oncotic pressure or colloidal osmotic pressure. Albumin generates about 70% of oncotic pressure. Oncotic pressure exerted by plasma proteins is about 25mm of Hg.
5. Plasma proteins, particularly Albumin helps in regulating acid-base balance in th blood. The plasma proteins are responsible for 15% of the buffering capacity of blood,
6. Plasma proteins provide viscosity to the blood. This viscosity is important to maintain normal blood pressure.
7. The tendency of RBC's to form rouleaux is accelerated by Globulin and Fibrinogen. Rouleaux formation is responsible for ESR value which is an important diagnotic / prognostic tool.
8. Globulin and Fibrinogen also help RBC's to keep them suspended in the blood
9. Leucocytes produce substances called Trephone. Trephones are produced from plasma proteins by Leucocytes. These substances are essential for nourishment of tissue cells.
10. Plasma proteins act as reserves. During fasting, inadequate protein intake or starvation, Plasma proteins are utilized by the body tissues as the last source of energy.