Proteins are composed of amino acids linked together by peptide bonds. They are essential to biological structure and function. Proteins can be classified as simple, conjugated, or derived based on their structure and components. The primary structure of a protein refers to the sequence of its amino acids, while secondary structure describes amino acid conformation into alpha helices or beta sheets. Tertiary structure describes the three-dimensional folding of polypeptide chains, and quaternary structure involves the aggregation of multiple polypeptide chains.

2. Name of student : Madhusha .M.L
Name of college : New B.Ed college,Nellimoodu
Option : Natural Science
Candidate code : 181/13376014

3. PROTEINS

4. PROTEINS
• Proteins are high molecular weight compounds made of
amino acids linked to one another by peptide bonds.
• On hydrolysis proteins yield amino acids
• Thus amino acids are considered as the building blocks of
proteins.

5. All proteins invariably contain carbon, hydrogen,
oxygen and nitrogen.
some proteins contain sulphur and phosphorus
as minor constituents.
Proteins have great importance in living systems.
They are indispensable for biological structure
and function.

6. CLASSIFICATION OF PROTEINS
There exist several arbitrary systems of classification
for proteins.
Based on the increasing complexity of structure,
proteins are mainly classified in to three groups.
They are the simple proteins, the conjugated proteins
and the derived proteins.

7. SIMPLE PROTEINS
Those proteins which yield only amino acids and their
derivatives on hydrolysis are called simple proteins.
They are further subdivided into seven subclasses in
the order of decreasing solubility.
They are albumins, globellins, glutellins, prolamines,
scleroproteins, histones and protamines.

8. CONJUGATED PROTEINS
• These are the proteins which contain a non protein
component (prosthetic group) in addition to the
protein part.
• The important types of conjugated proteins are
nucleoproteins, glycoproteins, lipoproteins,
chromoproteins, phosphoproteins and
metalloproteins.

9. DERIVED PROTEINS
These are the products obtained when native proteins
are degraded by acids, alkalis or enzymes.
Some of the derived proteins which are the
degradation products include proteoses, peptones,
peptides etc.

10. STRUCTURAL LEVELS OF PROTEINS
A protein may consist of one or more polypeptide
chains.
The linear chains of polypeptides are arranged in space
in various ways to give higher structural configurations
to proteins.
The different levels of structural organization shown
by proteins are primary, secondary, tertiary and
quaternary.

11. Primary structure refers to the number, nature and
sequence of amino acids in the polypeptide chain.
Secondary structure describes the conformation of
the polypeptide chains present in the protein
molecule.
There are two basic types of secondary structure
namely alpha helix and beta pleated sheet.

12. The tertiary structure of a protein refers to its three
dimensional structure which describes the spatial
arrangement of polypeptide chains.
In quaternary structure the polypeptide chains will
aggregate in a certain way to form a functional unit.

13. VARIOUS STRUCTURAL LEVELS OF PROTEINS

14. THANK YOU