Question

Process of joining of amino acids by peptide bond to form a polypeptide. How?

Answer 1

1. Activation of amino acids

AA+ATP+E → ^Mg+2AA-AMP-E+ PPi 

AA-AMP-E+tRNA →AA-tRNA+AMP+E

2. Initiation  

• Small subunit (40s) of ribosome binds with mRNA. 
• Charged tRNA specific for initiation codon reaches P site Larger subunit (60s) of ribosome now combines with 40s-m RNA—t 

3. Elongation

• Second t-RNA charged with amino acid occupies A site of ribosome. 
• Peptide bond formation between methionine and second amino acids with the help of enzyme peptide transferase.

4. Terminator 

• Translation stops when non sense codons (Stop codons) reached. 
• No t RNA for stop codons (UAA,UAG,UGA)