How are proteins classified on the basis of molecular shapes?

1.	How are proteins classified on the basis of molecular shapes?
Answer» On the basis of their molecular shapes proteins are classified as : (1) Fibrous proteins : The proteins in which the polypeptide chains lie parallel (side by side) to form fibre-like structure, are called fibrous proteins. The polypeptide chains held together by hydrogen bonds. These proteins are insoluble in water. The fibrous proteins are tough and insoluble in water, and dilute acids or bases. Example : myαin (in muscles), keratin (in hair, nails, skin), fibroin (in silk), collagen (in tendons), etc. (2) Globular proteins : The proteins have spherical shape. This shape results from coiling around of the polypeptide chain of protein, and have intramolecular hydrogen bonding are called globular proteins. They are soluble in water and dilute acids or bases. Example : Haemoglobin (in blood), albumin (in eggs), insulin (in pancreas), etc.

Answer»

On the basis of their molecular shapes proteins are classified as :

(1) Fibrous proteins :

The proteins in which the polypeptide chains lie parallel (side by side) to form fibre-like structure, are called fibrous proteins.

The polypeptide chains held together by hydrogen bonds.

These proteins are insoluble in water.

The fibrous proteins are tough and insoluble in water, and dilute acids or bases.

Example : myαin (in muscles), keratin (in hair, nails, skin), fibroin (in silk), collagen (in tendons), etc.

(2) Globular proteins :

The proteins have spherical shape.

This shape results from coiling around of the polypeptide chain of protein, and have intramolecular hydrogen bonding are called globular proteins.

They are soluble in water and dilute acids or bases.

Example :

Haemoglobin (in blood), albumin (in eggs), insulin (in pancreas), etc.

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