Bio Study Guide Proteins are made of amino acids that are strung together in a chain. Each 3-letter DNA sequence, or codon, encodes a specific amino acid. DNA-->mRNA-->Protein: Dna to mrna is called transcription, mrna to protein is translation DNA is a double helix, backbone is made up of sugar and phosphate DNA is made up of 4 nucleotides Adenine and Thymine always pair, Guanine and Cytosine always pair DNA Technology and Genomics E. Coli- an organism used to clone genes Restriction Enzyme- Used to cut DNA at a specific location for splicing Biotechnology-Using organisms or their components to make useful products Genetic engineering-direct manipulation of genes for practical purposes Plasmid- a small piece of bacterial DNA used for gene transfer