An amino
acid:
The R-group is different in
each of the 20 amino acids.
PRIMARY STRUCTURE
is…..
Carboxyl group
2 amino acids join in a ________________
Amino group
The primary structure of a polypeptide
determines the type and position of bonds
in the protein – so protein function depends
on the primary structure.
reaction to make a dipeptide. A
_________ molecule is lost in the reaction.
Fibrous
SECONDARY STRUCTURE
Globular
Polypeptide chains do not usually lie straight. ____________________
pull the chains into regular patterns, shown on the right:
 α- ______________________________
 β- ______________________________
TERTIARY STRUCTURE
Proteins are folded around themselves even more than the regular secondary
structure. This depends on the position of various bonds.
The function of the molecule depends on the tertiary structure – eg. enzyme
active sites. Changes can disrupt the tertiary structure and _____________ the
protein.
QUATERNARY STRUCTURE
is….
E.g. 1
E.g. 2
E.g. 3