Protein Synthesis Flashcards
(18 cards)
What happens in Transcription
DNA to RNA
What are the steps of transcription
1-RNA polymerase unravels the DNA
2-This is used as a complementary template
3-RNA is synthesised from 5’ to 3’
What are the 4 post-transcriptional modifications
Isomerisation
methylation
reduction
deamination
What do these modifications play a key role in
Tertiary structure of tRNA
What enzyme is used when loading the amino acid onto the tRNA
Aminoacyl tRNA synthetase
What are the two steps involved in loading the amino acid onto the tRNA
Amino acid activated by attachment of AMP
Amino acid transferred to 3-OH of tRNA
State the 4 stages of tRNA maturation
5’ to 3’ trimming via RNase
addition of CCA by tRNA nucleotidyltransferase
Splicing
base modifications
Steps of Translation
Initiation
Elongation
Termination
For the shine dalgarno Sequence what is the matching RNA sequence that binds to it during initiation of translation written 5’ to 3’
5’-AGGAGGU-3’
3’-UCCUCCA-5’
What happens during the initiation step
Ribosome binds to mRNA at shine-dalgarno sequence
Initiation factors help assemble ribosome and bind fMet-tRNA at the start codon
What are the 3 sites on the ribosome
EXIT
AMINOACYL
AND PEPTIDYL
In elongation what is the elongation factor (EF) responsible for ?
The delivery of the aminoacyl-tRNA to the A-site
What happens at the A site in elongation?
incoming aminoacyl-tRNA
What happens at the P-site during elongation
Holds the tRNA
How are peptide bonds formed during elongation
via peptidyl transferase
What’s the role of translocation during elongation
The ribosome moves 3 bases via EF-G+ GTP
What happens in termination
binding of RF1/2 triggers hydrolysis between bond of peptide and final tRNA
What are release factors (RF)
Proteins that bind specifically to mRNA stop codon sequences
