2.1.3 Proteins and enzymes
Proteins
Amino
Monomers are amino acids (aa)
acids o Polymer made up of monomers = protein
Important in growth and repair
Proteins are polymers made from repeating subunits of amino acids. There
are 20 naturally occurring amino acids.
Protein functions
Hormones
Enzymes
Signalling molecules
Antibodies
Fluid balance - reduce spikes in pH
Structural roles
Transport
Structure of proteins
Primary structure - order of amino acids in a chain
Secondary structure - how polypeptides are coiled. Joined by hydrogen
bonds.
Tertiary structure - 3D “global” shape of the entire protein molecule.
Quaternary structure - proteins with two or more polypeptide chains
Alpha helix and beta pleated sheets are the main two types of secondary
structure. Held together by hydrogen bonds
Protein structure basics
Built by ribosomes and modified in Golgi and ER
Most genes code for proteins
Four levels of protein structure
May be folded into a range of shapes
Long fibres, short chains, globular shapes
Feature Bonds Diagram
s
,Primar Sequen Peptide
y ce of bonds
amino
acids in
a
polypept
ide
chain
Second Folded Hydroge
ary structur n bonds
es - -
alpha causes
helix amino
and acids to
beta fold into
pleated repeatin
sheets g
pattern
, Tertiary Overall -
3D Hydroge
structur n bonds
e. Due -Ionic
to bonds
interacti -
ons Hydroph
betwee obic
nR interacti
groups ons
of -
amino Disulfid
acids e bonds
that
make
up the
protein.
Proteins
Amino
Monomers are amino acids (aa)
acids o Polymer made up of monomers = protein
Important in growth and repair
Proteins are polymers made from repeating subunits of amino acids. There
are 20 naturally occurring amino acids.
Protein functions
Hormones
Enzymes
Signalling molecules
Antibodies
Fluid balance - reduce spikes in pH
Structural roles
Transport
Structure of proteins
Primary structure - order of amino acids in a chain
Secondary structure - how polypeptides are coiled. Joined by hydrogen
bonds.
Tertiary structure - 3D “global” shape of the entire protein molecule.
Quaternary structure - proteins with two or more polypeptide chains
Alpha helix and beta pleated sheets are the main two types of secondary
structure. Held together by hydrogen bonds
Protein structure basics
Built by ribosomes and modified in Golgi and ER
Most genes code for proteins
Four levels of protein structure
May be folded into a range of shapes
Long fibres, short chains, globular shapes
Feature Bonds Diagram
s
,Primar Sequen Peptide
y ce of bonds
amino
acids in
a
polypept
ide
chain
Second Folded Hydroge
ary structur n bonds
es - -
alpha causes
helix amino
and acids to
beta fold into
pleated repeatin
sheets g
pattern
, Tertiary Overall -
3D Hydroge
structur n bonds
e. Due -Ionic
to bonds
interacti -
ons Hydroph
betwee obic
nR interacti
groups ons
of -
amino Disulfid
acids e bonds
that
make
up the
protein.
