5.In general, proteins can be classified into 3 different groups. Name and give a short description of each type and how they are distinct from one another. Provide an example of a macromolecule or other complex structure representing each of the three types.

 5.In general, proteins can be classified into 3 different groups. Name and give a short description of each type and how they are distinct from one another. Provide an example of a macromolecule or other complex structure representing each of the three types.

answer:

On the basis of composition proteins are classified into three groups viz. simple proteins, conjugated proteins and derived proteins.

1. Simple proteins

These are the proteins which consist of only amino acids – They do not contain other class of compounds.

2. Conjugated proteins

These are the proteins which consist of amino acids as well as other class of compounds.

They are further classified into six subgroups.

Table 4.1 Conjugated proteins

Sr. No.	Class	Other compound present	Example
1	Chromoprotein	Coloured pigment	Haemoglobin
2	Glycoprotein	Carbohydrate	Mucin (in saliva)
3	Phosphoprotein	Phosphoric acid	Casein (in milk)
4	Lipoprotein	Lipid	Lipovitelin (in egg yolk)
5	Nucleoprotein	Nucleic acid	Viruses
6	Metalloprotein	Metal	Ciruloplasmin (Cu)

3. Derived proteins

They represent various stages of hydrolytic cleavage of simple or conjugated proteins. e.g. proteoses, peptones, peptides, etc.