Question

List and discuss the many functions of proteins in the human body.

Answer 1

Proteins are of paramount importance for biological systems. Out of the total dry body weight, 3/4th are made up of proteins. All proteins are polymers of amino acids. By convention, long polypeptide chains containing more than 50 amino acids are called proteins.

Functions of proteins in the body :

• GROWTH AND MAINTENANCE - Protein is needed for the growth and and maintenance of the tissues. Body's proteins are in a constant state of turnover . Usually the body breaks down the same amount of protein that is being used to build and repair tissues. But in some other circumstances, the body uses more Protein than it can manufacture, hence the protein need of the body increases, example as in illnesses,old age , pregnancy, lactation etc. Also people with increased physical activities need more protein to meet their demands.
• HELPS IN BIOCHEMICAL REACTIONS - Certain proteins called Enzymes help in carrying out thousands of biochemical reactions that take place in the body. Enzymes allow themselves to combine with other molecules, to catalyse reactions, that help in the metabolism of the body. Many functions are dependent on enzymes such as digestion,energy production,blood clotting,muscle contraction etc. Any abnormalities in these enzymes can lead result in disease.
• HORMONES - Some of the hormones are made up of proteins that help in the communication system of the body i.e.. they help the cells, tissues and organs to communicate. They are made and secreted by the endocrine system and transported to the target cells or organs through blood. Examples are insulin, glucagon, ADH etc.
• STRUCTURE- Some of the proteins provide the cells and the tissues with structural integrity. These proteins include keratin, collagen and elastin. They help in formation of certain structures in the body. Keratin is a structural protein found in skin, nails and hair. Collagen is the most abundant protein in the body found in the bones, tendons, ligaments and skin. Elastin is very flexible and allows many tissues in the body to return to their original shape after stretching example lungs.
• MAINTENANCE OF pH - Proteins help the body in regulating the concentrations of acids and bases in the blood and other bodily fluids. A variety of buffering systems allows fluids to maintain normal pH ranges. Hemoglobin(a protein) binds small amounts of acid, helps to maintain the normal pH value of the blood.
• BALANCES FLUIDS- Albumin and globulin are proteins in the blood that help in maintaining the body's fluid balance by attracting and retaining water. They keep fluid balance between blood and surrounding tissues. Decreased amounts of these proteins will lead to decreased retention of blood in the blood vessels and fluid will be forced into the spaces between the cells leading to edema.
• IMMUNITY- Proteins play a major role in the immunity of the body because these proteins help in the formation of immunoglobulins or antibodies that help in fighting infections caused due to foreign invaders such as disease causing bacteria and viruses.
• TRANSPORTATION AND STORAGE - Some proteins act as transport and storage unit of the body. They carry substances into the cells, out of the cells or within the cells. These substances include nutrients like vitamins, minerals , oxygen etc. Protein transporters are specific in nature. Protein such as ferritin act as storage unit that stores iron.
• PROVIDES ENERGY - Proteins contains four calories per gram. When the body is under stress conditions and all the other sources of energy have been utilized , body can use proteins to make glucose for energy requirements.