How is elongation carried on during protein synthesis in a cell?
Ans17. After the initiation of the protein synthesis has taken place, the second step is the ‘elongation’. A second tRNA with an apprpriate anticodon and charged with an appropriate amino acid now forms hydrogen bonds with the second codon on the mRNA. This second aminoacyl-tRNA enters the ribosome at the A-site. A peptide bond forms between the initiation amino acid and the second amino acid. The peptide bond formation is catalysed by Peptidyl transferase. The first amino acid has got freed from the P site and is now attatched to the second tRNA as a part of the dipeptide attatched to it. The tRNA at the A-site is pulled to the P-site along with the mRNA. Thus the third codon comes in the A-site and the process is repeated with a third amino acyl tRNA coming at the A-site. Q18. What category of pathogens causes poliomyelitis? How is crippling caused in the victim of this disease? How can this disease be prevented? Ans18.Polio is caused by poliovirus. In CNS the virus destroys the dors
