What Are the Functions of Proteins

8/2/2019 What Are the Functions of Proteins

1/12

What are thefunctions ofproteins?


2/12

Proteins are by far the most

important of all biological compounds. The very word protein is derivedfrom the Greek proteios, meaning

of first importance , and thescientists who named thesecompounds more than 100 years agochose an appropriate term. Manytypes of proteins exist ,and theyperform a variety of functions,including the following


3/12

Movement

Every time we crook a finger, climb stairs,or blink an eye, we use our muscles.

Muscle expansion and contraction areinvolved in every movement we make.Muscles are made up of proteinmolecules called myosin and actin


4/12

Transport

A large number of proteins performtransportation duties. For example ,

hemoglobin , a protein in blood , carriesoxygen from the lungs to the cells in whichit is used and carbon dioxide from thecells to the lungs . Other proteins transport

molecules across cell membranes .


5/12

Hormones

Many hormones are proteins , includinginsulin ,erythropoietin ,and human growth hormone.


6/12

Protection When a protein from an outside source or

some other foreign substance (called anantigen) enters the body , the body makes itsown proteins (called antibodies) to counteractthe foreign protein .

This antibody production is one of the majormechanisms that the body uses to fightdisease. Blood clotting is another protective

function carried out by a protein ,this onecalled fibrinogen.

Without blood clotting ,we would bleed todeath from any small wound.


7/12

Storage

Some proteins store materials in the waythat starch and glycogen store energy .

For example, casein in milk andovalbumin in eggs store nutrients innewborn mammals and birds . Ferritin, aprotein in the liver ,stores iron.


8/12

Regulation

Some proteins not only control theexpression of genes ,thereby regulating

the kind of proteins synthesized in aparticular cell , but also dictate whensuch manufacture takes place.


9/12

Structure

We know that the main structural materialfor plants is cellulose .For animals, it is

structural proteins , which are the chiefconstituents of skin , bones , hair, andnails. Two important structural proteins arecollagen and keratin.


10/12

Catalysis

Virtually all the reactions that take placein living organisms are catalyzed by

proteins called enzymes.


11/12

Required for building and repair of body tissues (including

muscle)

Enzymes, hormones, and many immune molecules are

proteins

Essential body processes such as water balancing, nutrient

transport, and muscle contractions require protein to

function.

Protein is a source of energy.

Protein helps keep skin, hair, and nails healthy. Protein, like most other essential nutrients, is absolutely

crucial for overall good health


12/12

These are not the only function of proteins but they are the mostimportant . Clearly , any individual needs a great many proteinsTo carry out this varied functions.

A typical cell contains about 9000 different proteins: the entire humanbody has about 100,000 different proteins .

We can classify proteins in two major types;

Fibrous proteins, which are insoluble in water and are used mainly for

structural purposes.

Globular proteins, which are more or less soluble in water and are used

mainly for nonstructural purposes.

Documents

What Are the Functions of Proteins