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Protein synthesis

Protein synthesis is the process of production of protein in the body which is consistent with two key processes- translation and transcription.

Protein synthesis is the accumulation of two key processes namely translation and transcription by which proteins are produced in a body. This process is prevalent among prokaryotic as well as eukaryotic organisms. In prokaryotic organisms the synthesis occurs in the cytoplasm and eukaryotic organisms, the process of protein synthesis begins by the process of transcription which occurs in the nucleus. Further the transference of molecule from mRNA into ribosome in the cytoplasm, translation occurs where genetic code is analyzed thus completing the production of protein synthesis

Process of protein synthesis

The process of photosynthesis in eukaryotic organisms begins in the process of transcription. During this process DNA (Deoxyribonucleic acid) is used to make a molecule of messenger RNA (Ribonucleic Acid). The molecule of mRNA then departs from the nucleus reaching the ribosome in the cytoplasm, where the translation of the process takes place. During this process of translation, genetic code is analyzed and thus polypeptide is made.

Transcription

Transcription is the process of transference of genetic information from DNA to RNA. It occurs in the cell nucleus. In this process, a strand of mRNA is formed which is complementary to that of DNA, which is termed the gene. It can be easily identified from the sequence of DNA. Three steps included in the transcription: Initiation, Elongation, and termination.

  • Initiation: in this step of the process of transcription. In this process, the enzyme RNA polymerase is bound to a particular region of the gene called a promoter.
  • Elongation is the process of the addition of mRNA to the nucleotides.
  • Termination is the end stage of the process, in this process the formation of the mRNA strand is complete and it detaches from the DNA.

Processing of mRNA

This is the stage where the mRNA is termed pre-mRNA and it has gone through a certain extent of processing. These modifications will prove to be helpful in the production of multiple units of protein.

  • The 5′ caps protect the mRNA in the cytoplasm and help with its attachment to the ribosome.
  • With the usage of splicing, introns are removed from the protein sequence of mRNA. mRNA is further subdivided into introns and exons. Exons functions are the coding unit for the protein
  • Editing changes a few nucleotides from mRNA which causes it to take two different forms in some situations, for example, the protein APOB in humans.
  • Polyadenylation, which attaches a string of Adeline bases, signalling the end of the mRNA, exporting mRNA from the nucleus.

Translation

The translation is the last stage of RNA to protein synthesis. This process occurs after the exit of mRNA from the nucleus and enters the site of the ribosome, consisting of rRNA and protein. It reads the codon sequences in mRNA and amino acids are brought by tRNA, in the ribosome in the right order.

    • Initiation is the process, where tRNA joins the mRNA with similar start codons. mRNA, tRNA, and ribosomes together are called initiation complexes.
    • Elongation involves the process by which tRNA brings and attaches the amino acids to the polypeptide chain, as it continues to move into the ribosome. This tRNA leaves the ribosome once the transfer is complete, leading the ribosome to move down one codon length till a new tRNA brings along and attaches a new amino acid. The process continues and the chain continues to grow 
    • Termination is the stage at which the stop codon ends the stage of elongation. At the stop codon instead of tRNA, a release factor is summoned which breaks down the entire initiation complex.
  • Post Translational Modification, also known as PTM is the stage where after the biosynthesis of proteins, the proteins go through enzymatic and covalent modification. 

Site of protein synthesis

In prokaryotes, this process is carried out in the cytoplasm, whereas in the eukaryotes the process is a bit complex. It involves the sites of the nucleus, where the transcription begins moving towards the translation involving the initiation complex (mRNA, tRNA, and ribosomes)

Conclusion

The process of protein synthesis is responsible for the sustenance of genetic structure in turn the body of an organism. It mainly occurs in three different stages which involve the transcription which revolves around the transference of genetic information from DNA to RNA in the nucleus of a cell. It leads to the formation of an identical strand of RNA with the gene. The derived strand of mRNA further goes into processing. Later on, going through a translation stage involves the process of further elongation and then termination and completion of the mRNA strand formation.