7.3 Translation Flashcards
What process occurs when DNA turns into RNA?
transcription
What process occurs when RNA turns into protein?
Translation
RIbosomal RNA (rRNA)
RNA molecules used with proteins to make up ribosomes
-allow mRNA and tRNA to bind for translation
recap codons
Every three nucleotides
on mRNA
The way the codons are
arranged in groups of
three is called the
reading frame
what are the 3 steps of translation?
initiation
elongation
termination
what is the goal of translation?
to turn post-transcriptional mRNA code into an amino acid sequence
describe what happens during initiation
Ribosomal subunits
bind to mRNA at 5`
cap
Binds to start codon:
AUG
This always codes for
the amino acid
methionine
describe what happens during elongation
Ribosomes move along the
mRNA in 5🡪3 direction
Reads three nucleotides at a
time—reads codons
Each tRNA carries one specific anticodon and delivers the appropriate, corresponding amino acid to the ribosomes to build polypeptides
list the 3 spots that ribosomes have for tRNA to bind to during elongation
A site
P site
E site
A site
Aminoacyl site for aminoacyl tRNA to bind
P site
Peptidyl site for peptide bonds to form
E site
Exit site, for tRNA to prepare to leave the complex
describe what happens during elongation with the 3 sites
First tRNA brings methionine to P-site
Second tRNA brings next amino acid to A-site
Peptide bond formed between amino acids
Ribosome shifts over one codon; moving first tRNA
tRNA with met. now in in E-site
Next tRNA will always enter A-site
Process repeats until stop codon
what occurs during termination
Stop codon causes translation to terminate
Release factors cause the complex to dissassociate
releasing the mRNA and ribosomes
Protein folding then occurs, and the cell further modifies it for use
what are the 3 stop codons?
UGA, UAA, UAG
