DNA Protein synthesis
A piece of DNA that contains instructions to make a protein is called a gene. Each gene has the sequence for at least one polypeptide. Many complex proteins consist of more than one polypeptide, and the polypeptides are coded separately. Proteins form structures, and also form enzymes. The enzymes do most of the work in cells. Proteins are made out of smaller polypeptides, which are formed of amino acids. To make a protein to do a particular job, the correct amino acids have to be joined up in the correct order.