10 Differences between Prokaryotic and Eukaryotic Translation

Translation or protein synthesis is a process during which the genetic information is translated, following the dictations of the genetic code, into the sequence of amino acids in a polypeptide chain.  The synthesis of all proteins required for the cell is coded on genetic material DNA, which is transcribed to mRNA and translated to proteins. In simple words, Translation is a process in living cells in which the genetic information encoded in messenger RNA(mRNA) called genetic code in the form of a sequence of nucleotide triplets (codons) is translated into a sequence of amino acids in a polypeptide chain during protein synthesis.

Prokaryotic Translation vs Eukaryotic Translation

Prokaryotic translation	Eukaryotic translation
Coupled Transcription and translation. It is a continuous process as both transcription and translation occur in cytoplasm.	It is a discontinuous process as transcription occurs in nucleus while translation on cytoplasm.
As there is coupled transcription and translation. Therefore little mRNA processing	Extensive pre mRNA processing Removal of introns & joining of exons Addition of 5’ cap (7methyl guanosine) Addition of poly A tail
mRNA is polycistronic. mRNA with information for many proteins under a single control	mRNA is monocistronic. mRNA with information for only one protein or polypeptide under a single control
It occurs on 70 S Ribosomes -Consists of 2 subunits, 50S larger subunit and 30S smaller subunit.	It occurs on 80 S Ribosomes. -Consists of 2 subunits, 60S larger subunit  and 40S smaller subunit
Ribosome small subunit (30S) binds to Shine Dalgarno sequence during translation initiation and further detection of initiation codon	The 43S preinitiation complex (43S PIC) binds to the 5’ 7MeG cap of eukaryotic mRNA. Moves in 5’---3’ direction and finds AUG codon Presence of Kozak sequence (sequence in Eukaryotes with start codon favoring efficient initiation and translation)
Initiator tRNA is formyl methionyl tRNA (f Met tRNA) which codes for formyl methionine	Initiator tRNA is methionyl tRNA (Met tRNA) that codes for methionine
Initiation: 3 Initiation factors involved: IF1: binds to 30S subunit and prevents premature entry of tRNA to A site IF2-GTP: helps in binding of fMEt tRNA to 30S subunit IF3: binds to 30S subunit and prevents premature binding of 50S subunit and facilitates mRNA binding	Complex process involving ~12 eIFs (Eukaryotic initiation factors) -eIF1 and eIF1A, eIF2, eIF3, eIF4A, eIF4E, eIF4G, eIF4F, eIF5, eIF5A, eIF5B, eIF6
Elongation: 4 Elongation factors: EF-Tu: bringing aminoacyl-tRNA (aa-tRNA) to A site of the ribosome  EF-Ts: generates active EFTu EF-G: Translocation EF-P: Involved in peptide bond synthesis	4 Elongation factors: eEF1α: bringing aminoacyl-tRNA (aa-tRNA) to A site of the ribosome  eEF1 βϒ : generates active eEF1α: eEF2 :Translocation EEIF5A: Involved in peptide bond synthesis
Termination: 3 Release factors RF1: Release factor for stop codons UAA &UAG  RF2: Release factor for stop codons UAA &UGA RF3: facilitates binding of RF1 and RF2 to ribosome	Only one release factor eRF1: recognizes all three stop codons
Post translational modifications (PTMs): Relatively low number of PTMs in comparison with eukaryotic proteins. Occurs in cytoplasm Removal of formyl methionine	Extensive post translational modification Primarily Occurs in ER and Golgi before becoming a fully functional protein.
mRNA half life is short( few seconds to minutes) as mRNA is unstable.	mRNA has a half life of few hours to few days; it is quite stable.
It is a faster process, adds up to 17-21 amino acid residues per second.	Comparatively slower. Adds (up to 6-9 amino acid residues per second).

MCQ on translation