What are the primary, secondary, tertiary, and quartenary structure of proteins?
Primary structure is just the specific order of the amino acids that make up the polypeptide chain, there'll be 100 to 500 of them in a row, but sometimes less, sometimes more. They do -not- lie in a perfectly straight line but it makes it easier to think of this structure in that way.
Secondary structure is when the "straight line" of the primary structure curls into an alpha helix or folds into beta sheet shape. The H+ and O- attract to each other and the straight line folds into a coil or zig-zag that is the secondary structure.
Tertiary structure is when the protein / long chain of amino acids / polypeptide has a-helix, b-sheet, and primary structure all along the same polypeptide and the side chains of these different structures interact with each other and pull the different structures together into a kind of globular shape. This is the tertiary structure.
Quartenary structure is when two or more polypeptide chains are attracted to each other due to hydrogen bonding, ionic bonding, disulfide bridges, etc. and stick together due to these bonds.