Molecular of Translation Flashcards
Where does translation occur in the cell?
what does it require?
translation occurs in the cytosol
requires tRNA and rRNA
what is the start codon
AUG-Methionine
what is the stop codon
UAA, UGA, and UAG
do rRNA and tRNA go through transcription? how are they processed?
rRNA is processes by methylating some of the nucleotides
tRNAs are processed by adding a CAA to the end of the 3’ end
what does translation require?
Amino acids
mRNA
ribosomes
tRNA
what is translation?
biological polymerization of AA into polypeptide chains
main features of AA and bond formation
covalent bonds form between AA to form a polypeptide chain
main steps of translation
-ribosome holds mRNA to align codons with large subunit
-incoming tRNA is charged and carried a bound AA to A spot on large subunit
-once docked it aligns anticodons with codons on mRNA and moves to P spot
AA are attached to polypeptide
-tRNA exits ribosome at E site uncharged
what is the role of tRNAs in translation?
how do they become charged?
tRNA carries AA to A site on large ribosome subunit.
its charged by Aminoacyle-tRNA synthetase attaching the AA to it
4 levels of polypeptide structure
Primary
Secondary
Tertiary
Quaternary
3 tasks of ribosomes
-bind mRNA and identify start codon
-facilitate base pairing of codons to anticodons
-catalyze formation of peptide bonds between AA on polypeptide chain
main function of the small ribosome subunit
decode mRNA and facilitate binding of tRNA
main function of the large ribosome subunit
catalyze peptide bond
difference between bacteria, archaea, and eukaryotic ribosome subunit
eukaryotic ribosomes are larger(80S) that archaea and bacterial ribosomes(70S)
function of P, A, and E sites
P- holds tRNA that polypeptide is attached to
A- binds new tRNA to AA that needs to be added to the chain
E-where tRNA exits after adding AA
3 phases of translation
initiation
elongation
termination
how does initiation of translation differ between prokaryotes and eukaryotes
bacterial includes the shine-Dalgarno consensus binding sequence
what is a synonymous codon
codons consisting of differing nucleotides that code for the same AA
CODON vs ANTICODON?
what strand are they located on
codon: mRNA 3 nucleotide sequence
anticodon: tRNA sequences complimentary to mRNA codons
what does isoaccepting mean?
tRNA molecules with different anticodons for the same AA,
what nucleotides code for TRP
UGG
what is the wobble hypothesis
relaxation of strict complementary base pairing rules at the third base of the codon
