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).
Protein function
• You will have come across many proteins
before and covered some of the many roles
they undertake in living organisms.
• Research one of the proteins listed below and
complete its ID
helicase
keratin
kinase
oxytocin
integrins
phosphorylase
tubulin
insulin
actin
catalase
antibody
collagen
porin
elastin
polymerase
pepsin
myosin
cytochromes
haemoglobin
amylase
Protein name
Structure:
__(globular/fibrous)__
Location:
_____________________________
Function:
_____________________________
_____________________________
______________________________
Simple
diagram of
the protein
itself or
showing what
it does.
Glossary
• CONJUGATED PROTEIN – a protein which has a non-protein
component associated with it. Examples include glycoproteins,
lipoproteins and haemoglobin.
• FIBROUS PROTEIN – a protein which forms fibres and has a structural
rather than enzymatic function. Examples include keratin and
collagen.
• GLOBULAR PROTEIN – a protein which folds to give a complex 3-D
tertiary structure. Examples of these are enzymes, hormones and
antibodies.
• PEPTIDE BOND – The C-N bond linking two amino acids together.