Each gene directs the production of a protein. This protein makes sure a certain propertie in your body is expressed. A protein can, for instance, be an enzyme that triggers a particular reaction in your body. You can think of a protein as a long chain of amino acids. For the protein to do his job it often has to be rolled and folded in a particular way. This happens on a couple of levels: De primary structure The primary structure is the sequence of amino acids. This sequence makes the protein unique. De secundary structure the secondary structure consists of parts of the protein bound to each other. This can happen in 2 ways: in som sort of spiral and in a sheet-structure. the spiral is called an alpha-helix and the sheet a bèta sheet. De tertiary structure The tertiary structure is created when bridges are formed between alpha-helices and bèta-sheets, making the chain fold. The folded structure is then called a protein. De quaternary structure When multiple proteins are working together and form a complex it is called the quaternary structure. Often there are other molecules between these proteins, like iron, to activate the complex. Proteins can have many functions. For instance they can be bloodproteins, or hormones. Or enzymes, that often catalyze reactions in the body. Proteins can also function as transportproteins, to get certain molecules in or out of the cell. But proteins also play an important role in our immune system. The 4 different structures determine the final function of a protein and the place of functioning.