Explain what the stages of protein folding are and how the protein is held in its 3D shape

Break this question down into the four stages: primary, secondary, tertiary and quarternary and for each one describe the structure and what the non-covelant interactions are that hold the protein together. Make sure your sentences are clear and concise, not waffley!

There are four stages of protein folding, primary, secondary, tertiary and quarternary.

The primary structure is the sequence of amino acids held together by peptide bonds

The secondary structure is the protein beginning to fold up. It can have two types of structure: the alpha helix, a coil shape held by hydrogen bonds in the same direction as the coil. The beta pleated sheet is an S shape pattern, also with hydrogen bonds holding the structure together. The hydrogen bonds are between NH and CO groups on the peptides.

The tertiary structure is the protein folded into its precise 3D structure, relating to the functon. This is held together by a range of non-covelant interactions between side groups, including ionic interations, disuplhide bridges, hydrophobic interactions, Van der Waals forces and hydrogen bonds.

The quarternary structure is when single peptides bond to other peptides, for example in haemoglobin.