Biochemistry 2280A Lecture Notes - Lecture 4: Stem-Loop, Conformational Change, Aminoacyl-Trna
Document Summary
The genetic code spells out the amino acid sequence in 3 letter words called codons. Each codon represents an amino acid thus cells technically only need 20 or 21 different. There are 64 different ways to put together a codon as there are 4 different bases for each codons as there are 20 or 21 amino acids. A two letter code would provide 42 = 16 codons. This large number of possibilities in codons results in redundancy in the code. A key feature of the genetic code is that it is universal and that the code has evolved once; every organism uses the same code. Another key feature is that code is non overlapping; the problem with an overlapping code is that it would place significant restrictions of what amino acid residues could follow each other. An nonoverlapping code can have any amino acid in any order.