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The structure of proteins
Primary structure
This is the sequence of amino acids in the
polypeptide chain. It's important because the
sequence determines the eventual shape of the
protein and therefore its function.

There are 20 common amino acids and they can
be linked in any order along a polypeptide…

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Hydrogen bonding enables the chain of
amino acids (primary structure) to fold or turn
into itself to form either:
An - helix
A -pleated sheet

1) The - helix
H-bonds help keep the helix less
unstable. This helps globular proteins like
enzymes and antibodies maintain their
shape which is important…

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H-bonding between parallel chains results in
a flat structure which
becomes folded.
-pleated sheet are
rarer than -helixes and are
found in proteins with
structural functions e.g Silk.

Tertiary structure
This is the complex, 3D shape
the molecule forms when the
polypeptide chain twists and folds
around itself. The shape…

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Quaternary structure
Many highly complex proteins consist of more
than one polypeptide chain. The separate chains are
held together by:
Ionic bonds
Hydrophobic interactions




soooooo useful, thank you :D

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