Where do transcription & translation take place in a prokaryotic cell? Describe the three steps involved in translation?
In a prokaryotic cell, both transcription & translation occurs in the cytoplasm. It consists of the following steps:- Activation of Amino Acids:- amino acids are activated in the presence of ATP lay enzaminoacy tRNA Synthetase. Binding of Activated Amino Acid With tRNA:- Activated amino acids bind with specific tRNA to form charged tRNA. Initiation of Polypeptide Chain:- Initiation codon is AUG which codes for methionine. The initiation codon of mRNA binds to the p-site of the ribosome with the help of initiation factors. Elongation of Polypeptide Chain:- Second, activated amino acid along its tRNA reaches the ‘A’ site & binds to mRNA codon next to AUG. A peptide bond is formed between two amino acids by a peptidyl transferase. Ribosomes translate mRNA in -direction due to which free tRNA slips away &peptidyltRNA reaches P – site. Now the third amino acid reaches the A – site & the process continues. Termination of Polypeptide Chain:- When a termination codon (UAA, UAG, UGA) reaches at A- site translation terminates Since there is no specific tRNA for these codons.
