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Must: Describe how amino acids are linked
together by condensation to form
polypeptides.
Should: State that there are 20 different
amino acids in polypeptides synthesized on
ribosomes.
Could: State that Amino acids can be linked
together in any sequence giving a huge range
of possible polypeptides
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http://www.biotopics.co.uk/as/aminocon.htm
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Note this down
Condensation
reaction
Sequence/or
der of amino
acids
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Cut out the mRNA strand and stick it together.
Now cut out the 9 amino acid templates, then cut out the
9 R-groups to make 9 specific amino acids.
Then use the translation template to work out the order
of the amino acids.
 Cut out the Peptide bonds and use them to link the amino
acids together. The Carboxyl group on one amino acid
should be linked with the amine group on the next.
 A water molecule is released as this is a condensation
reaction.
What you have just modelled is the primary structure of a
protein.
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Caused by
hydrogen bonding
between amino
acid residues.
Will either form
alpha helix or betapleated sheet
The precise compact structure
unique to that protein which
arises when the molecule is
further folded and held in a
particular complex shape.
This is strengthened by Ionic
bonds, Disulfide bonds, Van
Der Waals forces and
hydrogen bonds.
Arises when 2 or
more proteins
become held
together,
forming a
complex
biologically
active molecule.
Use pages … from your textbook
to make a note of the main
differences between globular and
fibrous proteins.
A – 12
B – 20
C - 32
2.Which parts of amino acids are
involved in peptide bonds?
A. The carboxyl group on one amino acid
and the side chain on the other
B. The carboxyl group on both amino
acids
C. The amino group on one amino acid
and the carboxyl group on the other
D. The amino group on both amino acids
3.Which part of an amino acid
gives it its unique properties?
A. The amino group
B. The carboxyl group
C. The side chain
(hydrophobic) amino acids tend to be:
A. tucked away inside the protein.
B. exposed on the outside of the
protein.
C. distributed randomly throughout the
protein.
 Choose 5 amino acids and make
a protein! Link them together
with peptide bonds and show
how many waters are released.
8A What’s in food?
Testing for protein - In the
Biuret test the solution turns
purple.
copper
potassium
sulphate
hydroxide
shake
purple = protein
chopped
up food