Transcript Functional Variety of Proteins

Functional Variety of
Proteins
Proteins: organic compounds containing carbon
(C), hydrogen (H), oxygen (O), nitrogen (N) and
sometimes sulphur (S).
What I need to know:1. Proteins are held in 3d shape
2. Proteins are held by bonds
3. Types of proteins and their functions
Bonds in proteins
1. Peptide bonds
Proteins are build up of
sub-units called amino
acids. These are joined
together by chemical links
called PEPTIDE BONDS.
The sequence of
amino acids
determines the
protein’s structure
and function.
The product –
POLYPEPTIDE CHAIN
(eventually a protein)
AA1
AA2
tRNA
tRNA
U C G
A G C
A G C
U C G
A G G
2. Hydrogen bonds
Weak hydrogen bonds form between amino acids in a polypeptide
chain causing the chain to coil into a spiral.
3. Other linkages
There are different cross-connections that bridges sulphur
atoms with hydrogen bonds. These are important because
they determine the final structure of the protein and so
determine the function of the protein. They lead to the
formation of FIBROUS or GLOBULAR proteins.
Types of proteins
A HUUUUGEEE amount of proteins exist in living things –
the human body has 10,000 +.
They are classified as either:
Fibrous
Globular
Conjugated (Globular + non protein part)
Fibrous proteins
FIBROUS proteins are
formed by several spiralshaped polypeptide
molecules link together
giving it a rope-like
structure.
Example:
Collagen – found in bone
providing inelastic, rigid
support.
Globular protein
GLOBULAR proteins are
formed with polypeptide chains
fold into a spherical shape. This
type of protein are vital for all
living cells and perform many
functions:
Enzymes
Structural
proteins
Hormones
Antibodies
.
Conjugated proteins
These proteins are globular but also consist of a non-protein
chemical.
Examples:
GLYCOPROTEIN - made up of
protein and a carbohydrate. For
example, mucus that helps
lubricate and protect parts of the
body.
HAEMOGLOBIN – pigment that
transports oxygen in blood. Consists
of the protein globin and haem (nonprotein containing iron).