Proteins - Macromolecules:

The molecules which are very big in size and very complex in structure are considered as macromolecules. There are many numbers of macromolecules in the world such as carbohydrates, lipids, Nucleic acids, etc. One of such macromolecules is protein.

Proteins - body builders:

Yes, the proteins are very good body builders of the living organism. Whatever the structure acquired by an organism, proteins are responsible for that. There is some specialized structural proteins are there to determine the structure and shape of an organism. Apart from the structure and shape, proteins are responsible for many characters of the living organism. It determines the color, activity, physiological function, etc.

Proteins are mainly responsible for the growth of an organism. It provides tools for cell division, cell cycle, elongation of cells, growth of organs, etc. Because of these reasons, proteins are considered as "body builders".

Structure of proteins:

Talking about the structure of proteins, it is explained in four categories.

• Primary structure
• Secondary structure
• Tertiary structure
• Quaternary structure

Primary structure:

The basic fundamental functional and structural unit of protein structure is amino acids. In the primary structure, these amino acids lined up and bonded together in a single chain, which is called Polypeptide chain.

Secondary structure:

The polypeptide chain formed in the primary structure is folded well in the form of pleats. This folded structure is called secondary structure of proteins.

Tertiary structure:

The folded and pleated structure of proteins formed in secondary structure is compactly wounded to form as a ball wound of threads. For this wounding of polypeptide chain, disulfide bond is required.

Quaternary structure:

The many number of compactly wounded polypeptide chains linked together to form as a single protein. This structure is very complex and very hard to digest. To make this structure, peptide bonds and disulfide bonds will be needed.

General functions of proteins:

Proteins perform various functions in various forms:

• As antibodies
• As contractile proteins
• As enzymes
• As hormones
• As structural proteins
• As storage proteins
• As transport proteins
• As body builders
• As a mechanic for cell damage
• As a source of energy.