L18.pdf Translation PDF

These groups of three letters are called codons! The ultimate goal of translation is to create a long chain of amino acids—which is by definition a protein (or peptide or polypetide)! The directionality of peptide synthesis is said to be “N-to-C.” The 1st aa is Met, the 2nd aa is Phe, etc. Note synt...

These groups of three letters are called codons! The ultimate goal of translation is to create a long chain of amino acids—which is by definition a protein (or peptide or polypetide)! The directionality of peptide synthesis is said to be “N-to-C.” The 1st aa is Met, the 2nd aa is Phe, etc. Note synthesis is moving from the N-terminus (-NH3+) toward the C-terminus (-CO2-) “Redundant” is the exact vocabulary term, meaning that there are fewer amino acids than there are codon combinations, so multiple codons can encode for one amino acid It takes 3 mRNA bases (one codon) to code for each aa. Understand how to read this table to “translate” our triplet base codons into amino acids! To make a peptide of 400 aa would require 400 codons or 1200 mRNA bases. Though it would also require 1 stop codon as well. On an exam, if you were asked to translate a codon sequence to an amino acid, a Table of the Genetic Code would be provided! These are not included in our table to the left because Stop Codons do not encode for amino acids, they only signal the ribosome to stop protein synthesis The mechanism to attach an aa to a tRNA is complex, so, for BI108, it is not described. The 3’-overhang is 4 bases for 19/20 tRNAs. The anticodon sequence is written in the 3’-to-5’ direction to show how it base pairs with the codon which is written in the 5’-to-3’ direction. * In eukaryotic cells, Translation takes place in the cytoplasm, not in the nucleus. The Ribosome conducts the process called “translation.” This is an oversimplified description of translation. One STS Tutor learned to think of the LS and SS as like the buns of a hamburger with the RNA being the vegeburger between the two! LS and SS will only reunite when binding to a mRNA sequence to initiate Translation again! This is a simplistic view of the ribosome involved in Translation, but this is an appropriate level for BI108. The sequence of the cavaties E/P/A is significant. THE MATERIAL AFTER THIS POINT IS NOT ON QUIZ 3 THE MATERIAL ON THE NEXT 2 PAGES IS NOT ON QUIZ 3 The 2nd and the 3rd tRNAs have the potential to have any amino acid attached, but the 1st tRNA will always be bonded to Methionine. This can be confusing because protein synthesis is initiated in the middle cavity and ends at the first cavity, but the order of this matters! MATERIAL ON THIS PAGE IS NOT ON QUIZ 3. The peptide is released from the tRNA and the ribosome complex, and mRNA, RFs, LS, and SS all disassociate!