L22 Translation: Ribosomes Flashcards
Which statement regarding ribosomes is false?
a) They are ribonucleoprotein complexes
b) They are highly abundant
c) They are synthesised from rRNA
d) 70S subunits are composed of 50S + 20S subunits
d) 70S subunits are composed of 50S + 20S subunits
False, 70S subunits are composed of 50S + 30S subunits (S = svedberg unit, which measures sedimentation and not mass)
The three phases of translation are…
- Initiation 🏁
- Elongation 🤥
- Termination ✋
In initiation, energy is provided by…
GTP hydrolysis
Initiation factors…
IF1, IF2, IF3
Elongation factors…
EF-Tu, EF-T, (EF-G + GTP)
Termination of translation occurs at the…
Stop codon
Release factors
RF1, RF2
The ribosome binds to the ribosome binding site (RBS), known as the…
Shine-Dalgarno sequence
Which subunit binds first?
a) 70S
b) 50S
c) 30S
c) 30S
The 50S subunit has 3 sites, knowns as…
E, P, A
5’ -> 3’ mRNA
The ribosome binds to the mRNA by…
RNA-RNA base pairing
The ribosome is rich in RNA
In initiation, the initiator tRNA displaces…
Initiation Factor 3 (IF3)
After the initiator tRNA has displaced the initiation factor 3, the…
50S subunit joins
The joining of the 50S subunits is followed by the hydrolysis of GTP, which leads to the release of (3)…
- IF1
- IF2
- GDP + Pi
In elongation, new tRNA binds at the…
A site
e.g. ‘added’ - A
