Translation in Prokaryotes vs Eukaryotes
There are several meanings for the term translation, but when it comes as either prokaryotic or eukaryotic translation, its contextual meaning refers to one of the processes in gene expression and protein synthesis. There are differences in the process of translation between prokaryotes and eukaryotes, which are described concisely in this article.
When the mRNA strand is being processed to translate into protein at the ribosomes, the prokaryotic translation is said to be in action. There is no nuclear envelope in prokaryotes, and the non-coding nucleotides are also absent. Therefore, the RNA splicing does not take place, and the ribosomal subunits can directly start translation as the mRNA formation takes place in prokaryotes. The tRNA molecules carry amino acids that are specific with the anticodon.
As the transcription takes place, the two ribosomal subunits (50S and 30S units) along with the initial tRNA molecule assemble together at the mRNA strand. The next tRNA molecule (based on the codon sequence in the mRNA strand) comes to the large ribosomal subunit, and the two amino acids attached to the tRNA molecules are attached with a peptide bond. The peptide bonding is continued as per the codon sequence of the mRNA strand and a protein called release factor stops the translation process. In prokaryotic translation, there can be few proteins synthesized in one step. Additionally, few translations can take place simultaneously in prokaryotes though polysomes. It would be important to state that tRNA molecules are not dissolved after peptide bond is completed, but can carry additional amino acids to contribute for translation in prokaryotes.
Conversion of information in the transcribed mRNA strand into proteins in eukaryotic organisms is the eukaryotic translation. However, with the presence of both coding and non-coding nucleotides in eukaryotes, the splicing of those from the RNA strand has to take place before the mRNA strand is ready for translation. Additionally, the presence of nuclear envelope does not allow the ribosomes to get close to the genetic material in the nucleus. Therefore, the translation process takes place outside the nucleus or in the cytoplasm.
There are two main ways of initiation in eukaryotic translation known as the cap-dependant and cap-independent. There is a special protein with a tag attached to the 5’ end of the mRNA strand, which binds to the small ribosomal subunit (40S unit). The translation continues with the assemblage of large ribosomal subunit (80S unit), small subunit with mRNA strand, and tRNA with amino acids. The peptide bonding takes place after that and the eukaryotic release factors terminate the process after the protein is synthesized.
What is the difference between Prokaryotic and Eukaryotic Translation?
• As there is no nuclear envelope, prokaryotic translation takes place close to the genetic material. However, eukaryotic translation takes place in the cytoplasm and never inside the nucleus due to the presence of nuclear envelope.
• Protein capping and RNA splicing take place before translation in eukaryotes, but there are no such steps in prokaryotic translation.
• Translation starts as the dismantling of the DNA and synthesizing of mRNA strand take place in prokaryotes, but eukaryotic translation starts after completion of mRNA synthesis and protein capping with splicing.
• Involved ribosomal subunits in prokaryotic translation are 30S and 50S while eukaryotes have 40S and 80S ribosomal subunits in translation.
• Initiation and elongation are more complex factor-aided processes in eukaryotic translation than in prokaryotic translation. However, the terminations are almost the same in both organisms.