Genetic Code - translation Flashcards
(17 cards)
Translation
nucleotide to protein
triplet nucleotide code
influences flow of genetic information from DNA to mRNA to protein
codons
a series off non overlapping, three-nucleotide
codon
sequences specify a specific amino acid for synthesis off polypetides
genetic code
4 nucleotide bases, 64 codons, 20 amino acids
- nearly universal
synonymous codons
different codons that encode the same amino acid
sense codons
specify a specific amino acid
start codon
AUG, starting point for translating the mRNA genetic code into polypeptides
stop codons
UAA, UAG, UGA don’t code for an amino acid and terminate translation of the mRNA genetic code
Untranslated region
mRNA sequence upstream of start codon and downstream from stop codon is not translated
reading frame
defined as mRNA sequence starting at the start codon and ending at the stop codon
translation
mRNA directed protein synthesis
tRNA
pair to mRNA codons and transfer amino acids to the growing polypeptide in a ribosome
ribosome
facilitate specific pairing of tRNA anticodons with mRNA codons
- two ribosomal subunits are made of proteins and ribosomal RNA
Binding sites of ribosome
- a site holds the tRNA that carries the next amino acid to be added to the chain
- p site holds the tRNA that carries the growing polypeptide chain
- e site is the exit site where tRNA leave the ribosome
translocation
process that advances the mRNA-tRNA moiety in the A site to the P site. empty tRNA is advanced from he P site to the E site. opens the A site for translation of the next codon
steps of translation
initiation
elongation
termination
5’ - 3’
