general properties of proteins 3.1.4.1

general properties of proteins 

• amino acids are the monomers from which proteins are made.
• https://goo.gl/images/GESYTm - structure of amino acid 
• the general structure of an amino acid is shown as above 
• the twenty amino acids that are common in all organisms differ only in their r-group
• a condensation reaction between two amino acids forms a peptide bond
• https://goo.gl/images/DXQzHX- condensation reaction
• dipeptides are formed by the condensation of two amino acids 
• polypeptides are formed by the condensation of many amino acids 
• a functional protein may contain one or more polypeptides 
• functional protein carry out a function in the body ( antibodies) where structural proteins produce structure (bones and muscles )

protein structure 

• primary structure - sequence of amino acids in a polypeptide chain
• secondary structure- alpha helix is a coil and beta pleated sheets (folds)
• this occurs where 2 or more parts of the chain run parallel to each other and form hydrogen bonds 
• the sequence of amino acids determine the alpha helix or beta pleated sheet 
• …