Translation is the process of synthesis proteins from an mRNA template

Translation is the process of synthesis proteins from an mRNA template. The sequence of nucleotides on the mRNA act as a template is translated into the amino acid sequence of proteins .This reaction is carried out by ribosomes.
There are three types of RNA which are mRNA(messenger RNA) , rRNA(ribosomal RNA) and tRNA(Transfer RNa). The messenger RNA is a single stranded RNA which carry genetic information transcribed from DNA in nucleus through the pores in the nuclear envelope to ribosomes for translation in cytoplasm to be used in protein synthesis. The ribosomal RNA is the major component of ribosomes. Ribosome is the site of protein synthesis. Each ribosome is composed of two subunits which is one small subunit as binding site for mRNa , start and one large subunit as binding sites for three tRNA molecules which are E site(exit site), P site (peptidyl-tRNA binding site) and A site(aminoacyl-tRna binding site). During protein synthesis, the small and large subunit sandwiched a mRNA molecule between them. The transfer RNA is a single stranded RNA which is folded back to form a 3D compact shape. tRNA is used to deliver amino acid to the ribosome for protein synthesis based on their specific base pairing between trna which have three exposed base known as anticodon and and mrna codon. Trna will bind with the amino acid that matches the code for the right mrna codon so that the translation is accurate. The process of which the specific amino acid attaches to the trna molecule to form aminoacyl – trna is activation.
There are also 3 stages in translation which are initiation, elonagation and termination. During the initiation stage, it begins when a small ribosomal unit binds to the mrna. The initator aminoacyl –trna that carries methionine (met) binds to the start codon (AUG) on the mRNA completing the translation initiation complex. The AUG codon in the mrna form base pairing with the UAC anticodon of the methionine( met) trna.initiator trna locates at p site of ribosome and a site is empty. Thus , itt is available for next aminocyyl –trna to enter.
Stages 2 of translation is elongation. Amino acids is added one by one to the previous amino acid at the A site. The correct trna binds to the ribosome through complementary base pairing. Ribosomal RNA then catalyzes the formation of a peptide bond between the first and second amino acids where the first methionine appears to have been ‘transferred’ to the tRNA on the A site. Once the peptide bond is formed, the empty tRNA exits the ribosome and the tRNA on the A site moves into the P site. This process is known as translocation. This results to have an empty A site, which is ready for the third tRNA. This process is continue until all the codon of mrna is translated and reaches a stop codon.
Stage three of translation is termination. Termination is the point which when the stop codon reaches the A site, (UAG UAA UGA) AND as a signal to STOP THE TRANSLATION PROCESS. This is because no trna will bind to a stop codon. Then, a protein that recognize the stop codon which is known as release factor binds to A site to stop the codon. As a result, water molecules is added to the polypeptide chain to hydrolyzed the bond between the polypeptide and the trna in the p site. The completed polypeptide and trna leaves the ribosome and dissociates into two subunits.
There are also some ribosome which can translate mrna at the same time is called polyribosome. By doing this, more identical protein can be made on a shorter time and this increase the rate of protein synthesis.


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