One gene = production of a specific enzyme. Now we know that not all proteins are enzymes. Transcription = information in dna is used to synthesize messenger rna (mrna) Translation = ribosome uses mrna to synthesize a polypeptide. Proteins = 20 possible amino acids and polypeptide bonds. Codon = mrna => 3 nucleotides = triplet codes. Ribosome doesn"t start until it finds aug trna helps ribosomes read codons. Promoter = start site for transcription (where the gene starts and transcript) Binds to promoter, opens up helix, read sequence. Dna template strand read in 3" to 5" direction. Rna polymerase elongates mrna in 5" to 3" direction. Specific dna sequences signal rna to stop transcripting. Newly formed transcript rna falls off dna template or helped off by protein mrna processing (only in eukaryotes!) Rna processing = eukaryotic cells modify rna after transcription before going to the cytoplasm.