Explain the process of translation in a bacterium ( prokaryotes ) ( No links please )
Translation is the process in which mRNA produced by transcription is decoded by the ribosomes to produce a specific amino acid chain.
Protein synthesis occurs in the following steps:
Activation of tRNA: This step occurs before the process of translation and is an essential step as it loads the amino acids on their respective tRNA. Only activated tRNA are required to form peptide bond between two amino acids.
Initiation - It involves binding of small ribosomal subunits to mRNA and then is joined by the 50S subunit. It includes steps of formation of the peptide bond between the first two amino acids. Protein synthesis is initiated with the amino acid methionine because the AUG translation initiation codon of mRNAs is recognized by the anticodon (UAC) of initiator methionine transfer RNA.
Elongation - It includes all the reactions from the synthesis of the first peptide bond to the addition of the last amino acid.
Termination- In the termination step, the completed polypeptide chain is released and the ribosome dissociates from mRNA. The tRNA recognises a stop codon and stops the synthesis of proteins.
Three codons on mRNA which are not recognized by tRNA are UAG (amber), UGA (opal), UAA (ochre). These codons are collectively known as nonsense codons or terminator codons. They are significant since their presence bring the termination of protein synthesis (translation).
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