Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance3 Marks
Question
Explain in brief the process of initiation during protein synthesis.
✓
Answer
Initiation of synthesis of polypeptide chain takes place as follows:
Small subunit of ribosome binds to the $ \text{m-RNA}$ at $5\ ’$ end.
Start codon is positioned properly at $P-$site.
Initiator $ \text{t-RNA}, ($carrying methionine in eukaryotes or formyl methionine in prokaryotes$)$ binds with initiation codon $ \text{(AUG)}$ of $ \text{m-RNA}$ by it’s anti$-$codon $ \text{(UAC)}$. Codon$-$anti$-$codon pairing involves formation of hydrogen bonds.
The large subunit and smaller subunit of ribosome bind in the presence of $Mg^{++}.$
Thus, initiator charged $ \text{t-RNA}$ occupies the $P-$site and $A-$site is vacant for next charged $ \text{t-RNA}.$
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