Protein synthesis is a process by which the cells in a body make proteins, by means of DNA and RNA. Simply stating, protein synthesis is the creation of proteins in the body. At times, proteins can be synthesized directly from genes by translating mRNA. However, when a protein is harmful and needs to be available on short notice or in large quantities, a protein precursor is produced. The precursor is an inactive protein (or peptide) that can be turned into an active form by posttranslational modification. Protein synthesis can also be described as the process, by which the genetic code in the DNA is decoded through the different kinds of RNA into proteins. This would, in turn, spell out the traits that have been passed on from parent to offspring, including those that came from other members of the family. Read on to know what is the process of protein synthesis.
The Process Of Protein Synthesis
The process of protein synthesis essentially starts in the nucleus or the brain of the cell. It is, here, that the DNA is held. The structure of the DNA comprises of two chains of sugars and phosphates, joined by pairs of nucleotides deoxyadenosine, deoxyguanosine, thymidine, and deoxycytidine. Just like the duplication of DNA, the DNA is ‘unzipped’ by the enzyme helicase, leaving the single nucleotide chain open to be copied.
Thereafter, the RNA polymerase comprehends the DNA strand, synthesizing a single strand of messenger RNA (mRNA). The mRNA thus formed, leaves the nucleus through the pores and gets into the cytoplasm. It is, here, that it mixes with the ribosomes, initializing the process of protein synthesis, which occurs by the formation of peptide bonds and polypeptide chains.
It is the process of converting the mRNA codon sequences into an amino acid polypeptide chain. This takes place in three phases - initiation, elongation and termination. During the initiation phase, a ribosome attaches to the mRNA and starts to code at the FMet codon (usually AUG, sometimes GUG or UUG). The next phase is the elongation phase, wherein the tRNA brings the corresponding amino acid to each codon, as the ribosome moves down the mRNA strand. In the third phase i.e. termination, reading of the final mRNA codon takes place, which ends the synthesis of the peptide chain and releases it.