Proteins

• Amino acids are the monomers from which proteins are made.
• NH2 represents an amine group. COOH represents a carboxyl group. R represents a residual group.
• A condensation reaction between two amino acids forms a peptide bond.
• A functional protein may contain one or more polypeptides.
• A primary structure is the sequence/order of amino acids.
• The secondary structure is when the amino acids chain becomes longer it is folded into specific shapes formed via hydrogen bonding (a-helixes, b-pleating)
• The tertiary structure is the overall 3D shape created by different regions of folding and the interactions between the side groups. They have hydrogen bonds, disulfide bridges and ionic bonds.
• The quaternary structure of more than 1 polypeptide subunit interact allowing a resulting function eg Haemoglobin, Collagen.
• The biuret test is the test for proteins. You add sodium hydroxide and a few drops of copper sulphate solution. If the solution has protein it will turn purple.