To get a sense of the complexity of a protein, imagine a string of a few hundred beads with countless attractions between different beads. The result would be a big lump of beads in an incredible complex arrangement. Replacing the beads with amino acids give you some sense of what a protein is like. The order in which the amino acids are put together determines the properties of the resulting protein because the order also determines the interactions between the amino acids. There are four levels of three-dimensional protein structure , all of which begin with amino acid arrangement.
Primary structure is the order of the amino acids in the protein chain.
Secondary structure consists of interactions between amino acids along the protein chain. These interactions are caused by attractions between amino acid R-groups. An alpha helix occurs when bonding attractions twist the protein chain into a spiral or curlicue. A curly french fry and springy curled ribbon are analogies for how alpha helices appear. A beta-pleated sheet occurs when the components of the chain attract each other in such a way that they appear as a flat wrinkly sheet.