Molecular Biology

Roteins the Building Blocks of Life

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Proteins are the most important molecules in a cell. These are involved in almost all functions that go on in the cells. However, every function in the cell has a different set of protein molecules performing that function. Some protein molecules are involves in providing the cell its structural support, while other are involved in its mobility, or in its defense system against the germs.

There are many variations of proteins. They may vary in shape or they vary in function. Yet, every kind of proteins molecule is composed from a combination of twenty amino acids. Each type of protein molecule has a three dimensional shape. Below, a list of a variety of different types of proteins and their functions are described.


Antibodies: These are special proteins that functions as defense system of the body against the antigens, the foreign invaders, such as bacteria, virus, etc.  Antibodies destroy the antigens by immobilizing them which is followed by their destruction by white blood cells.   

Contractile Proteins: These types of proteins are involved in movement. Examples of these contractile proteins include actin and myosin. These proteins are responsible for muscle contraction and movement.

Enzymes: These protein types are responsible to facilitate all the biochemical reactions that are going on within the cells. They are more frequently known as catalysts as they speed up the cell’s chemical reactions. Examples of these types of proteins include the enzymes lactase, pepsin, etc.  

Hormonal Proteins: These types of proteins are the messenger proteins. These are used to coordinate certain activities in the body. Examples are insulin, oxytocin, and somatotropin. Insulin is used to regulate the metabolism of glucose to control the blood-sugar concentration. Oxytocin is responsible for contraction of uterus in females during delivery. Whereas somatotropin, the growth hormone, stimulates the production of proteins in muscle cells.

Structural Proteins: These proteins form the supporting tissue of the body. These may include include keratin, collagen, and elastin, which provides support the connective tissues such as tendons and ligaments.

Storage Proteins: These proteins types store amino acids.

Transport Proteins: These types of proteins are carrier proteins. They are involves for the movement of molecules within the body, from one place to another. Examples of these transport proteins include hemoglobin and cytochromes. Hemoglobin is protein that is responsible for transporting oxygen within blood. On the other hand, cytochromes as electron carrier proteins in the electron transport chain. 

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