Watch my new presentation on the topic proteins

1. PROTEINS
Saranya H C
Keyi Sahib Training College

2. • Proteins are complex organic
substances which are the basis of
cytoplasm and are found in all living
organisms
• Polymers of amino acids which are
linked by peptide bonds

3. Therearemainlytwotypesofproteins
1. Fibrousproteins
2. Globularproteins

4. FIBROUS PROTEINS
• Fibrous proteins have
thread like molecules,
lying side by side to
form fibres.
• They are insoluble in
water.
• Serve as the chief
structural material of
animal tissue.

5. GLOBULAR PROTEINS
• Globular proteins have
molecules which are
folded into compact
units that often have
spherical shapes
• They are soluble in
water
• Some of them function
as enzymes

6. The structure of proteins
may be discussed as,
• Primary structure
• Secondary structure
• Tertiary structure

7. PRIMARY STRUCTURE
The primary structure of
a protein refers to the
sequence of amino acids
in the polypeptide chain.
The primary structure is
held together by peptide
bonds that are made
during the process
of protein biosynthesis

8. SECONDARY STRUCTURE
The conformation which
the polypeptide chain
assume as a result of
hydrogen bonding is
referred to as secondary
structure of proteins.

9. TWO TYPES OF SECONDARY STRUCTURE
• Alphahelix structure
• Beta pleated sheet structure
In alpha helix
structure, the
polypeptide
chains are coiled
upto form a
Spiral structure
called helix
In beta pleated sheet
structure, the peptide
chains lie sideby sidein a
zig-zag manner. The
neighbouringchains are
held together by hydrogen
bonds resultingthe
formationof a sheet.

10. TERTIARY STRUCTURE
In tertiary structure the
entire molecule folds up
to produce a specific
shape. That is they
represent the complete
three diamension of
proteins.

11. On heating or treating with
chemical reagents, most of
the proteins undergo
changes in their physical
properties and they also
loses their biological
activity. This phenomenon
is called denaturation of
proteins.
Protein denaturation

12. FUNCTIONS OF PROTEINS
• Sources of energy for metabolic
processes
• Some proteins act as biological
catalysts
• Maintain sugar level in the body
• Defend against the invasion of
foreign organisms in the body
• Some proteins form blood reserves