Protein synthesis is the process of producing proteins through genetic coding. In this process DNA is transcribed into RNA. Once it transcribed, mRNA molecule is created to synthesize proteins.
This process is same in both eukaryotes and prokaryotes, but there are some differences that you need to know about them. This article will give you short details on How Is Protein Synthesis Different In Prokaryotes And Eukaryotes Apex.
Prokaryotic protein synthesis is more efficient than eukaryotic protein synthesis.
Protein synthesis is the process in which cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription of nuclear DNA into messenger RNA, which is then used as input to translation. Prokaryotic protein synthesis takes place in the cytoplasm.
The mRNA is translated by the ribosome at the same time as it is being transcribed by RNA polymerase. As a result, a single mRNA molecule may be translated simultaneously by several ribosomes. This allows for efficient utilization of scarce resources and rapid responses to changes in the environment.
Eukaryotic protein synthesis takes place in both the nucleus and cytoplasm. The mRNA has to be processed before translation can happen in the cytoplasm. For this reason eukaryotic protein synthesis does not occur at such a rapid rate as prokaryotic protein synthesis even though there are many more ribosomes available in eukaryotes than prokaryotes.
Formation of eukaryotic mRNAs in nucleus and their transport to the cytoplasm.
In many eukaryotic cells, the mRNAs are first synthesized within the nucleus, and are then transported to the cytoplasm where they are translated. In contrast, in prokaryotes, mRNA synthesis takes place in the cytoplasm. This difference between eukaryotes and prokaryotes is due to a number of reasons:
Prokaryotes do not have a nucleus, so all their transcriptional and translational processes take place in the cytoplasm. Eukaryotes have a nucleus that separates the transcriptional process from translation. Hence, mRNAs have to be synthesized within the nucleus and then exported to the cytoplasm before they can be translated into proteins.
In eukaryotes, the DNA molecules are present not as circular chromosomes but as linear chromosomes. These linear chromosomes are packed into compact structures called chromatin fibres that allow only one side of the DNA molecule to be accessible for transcription at any given time.
Thus, it is necessary to synthesize an RNA molecule that can bind along its entire length with a single strand of DNA in order to ensure proper regulation of transcription (i.e., RNA synthesis). A part of mRNA is continuously exposed to cytosol during
Translation starts when the ribosome binds to the start codon, AUG, on a mRNA.
The translation of mRNA into protein is called protein synthesis. It occurs in the cytoplasm. Translation starts when the ribosome binds to the start codon, AUG, on a mRNA. The start codon begins the process of decoding the mRNA sequence into the amino acid sequence that makes up a protein molecule. The process of translation requires three tRNA molecules and three other RNA molecules:
- The anticodon of each tRNA molecule recognizes one codon on the mRNA molecule.
- Ribosomal RNA (rRNA) holds together two subunits that make up the ribosome (a large RNA-protein complex).
- Messenger RNA (mRNA) carries instructions from DNA for making a protein from amino acids.
Processing or modification of prokaryotic mRNA before translation is minimal or absent.
Processing or modification of prokaryotic mRNA before translation is minimal or absent. The process of transcription in prokaryotes is somewhat simpler than that in eukaryotes, primarily because RNA processing (splicing and polyadenylation) does not take place in bacteria. Upon transcription, the nascent pre-mRNA is generally ready for translation immediately.
Eukaryotic mRNAs undergo a series of modifications during and after transcription. These modifications allow for efficient translation of the information contained within the mRNA.
Although eukaryotic genes typically contain introns (noncoding sequences), these are spliced out before or during transcription with the result that only exons (the coding regions) remain. The last step in the processing of eukaryotic mRNAs, then, is to add a poly A tail to the mRNA before it leaves the nucleus.
Introns are removed in a series of reactions catalyzed by spliceosomes consisting of snRNPs and other proteins. Splicing reactions involve formation of hydrogen bonds between complementary nucleotides in the intron and at the 5′ and 3′ ends of the exons to be joined.
The intron is then released as lariat-shaped molecule with a 2′,5′-phosphodiester bond at its branch point. The two exons are then covalently linked, forming a mature mRNA molecule.
Processing or modification of prokaryotic mRNA before translation is minimal or absent. However, after transcription and splicing in eukaryotes, the mature mRNA may undergo further processing steps that include addition of a 5′ cap and polyadenylation.
Last Words
Prokaryotes have a much simpler system of protein synthesis than that of Eukaryotes. The main difference is in the structure of the ribosomes.