How does Euk translation mechanism differ from Prok at initiation?
Euk mRNAs are processed prior to translation

The primary enzyme involved in translation
The ribosome, which functions as a ribozyme

Enzyme which catalyzes the peptide bond
pepitdyl transferase

Named subsections of a tRNA
3 loops: D loop, anticodon loop (interacts with mRNA), T-Psi loop

Where the amino acid attaches to the tRNA
The 3'-OH; a universally conserved CCA sequence at the 3' end

Prok ribosome is composed of these
50S and 30S subunits

Euk ribosome is composed of these
60S and 40S subunits

The three tRNA binding sites on a ribosome
A-site: aminoacyl site, decoding site for incoming mRNA; P-site: peptidyl site, holds the nascent peptide chain; E-site: holds deacylated tRNA before leaving the ribosome

Prok translation initiation: three initiation factors
IF-1: blocks A-site; IF-2: promotes tRNA binding to P-site; IF-3: prevents association of large subunit

Prok translation initiation: unique method
mRNA binds via Shine-Dalgarno sequence; base-pairing between mRNA and rRNA; allows internal initation and polycistronic mRNAs

Euk translation initiation notes
Scanning ribosome; small subunit recognizes 5' cap; many initiation factors; scan from cap to first AUG; no polycistronic mRNA; cannot initiate internally.

This delivers tRNA to A-site
EF-Tu-GTP

tRNAs must decode mRNA here
A site

Ribosome translocates with this
EF-G-GTP

Termination notes
When stop codon is in A site, no decoding; Termination factor (release factor) binds; completed peptide is hydrolyzed from tRNA; ribosomal subunits separate; ribosome reinitiates on a new mRNA