The DNA sequence must first be copied by messenger RNA in a process called transcription. The mRNA makes a complementary strand based on the DNA code. For example, if the DNA codes read TACGGCATT, the complementary mRNA would be AUG-CCG-UAA. Notice that base pairing rules apply except in RNA, there is no thymine so you must substitute the base uracil. The transcript is brought to a ribosome where protein synthesis occurs. Transfer RNA molecules will bring the appropriate amino acids into position according to the triplets or codons found in the mRNA. For example, the first triplet is AUG, this codes for the amino acid known as methionine or start. It signals translation is to begin resulting in a chain of amino acids that will ultimately form a polypeptide. This will detach from the ribosome when a stop codon is reached, then fold into a functional protein molecule.