The hydrolytic step leading to release of polypeptide chain from ribosomes in catalysed bya) Stop codonsb) Pepitidyl transferasec) Release factorsd) AUG codone) Dissociation of ribosomes

**Question:** The hydrolytic step leading to release of polypeptide chain from ribosomes in catalysed by:

1. Stop codons
2. Peptidyl transpeptidase
3. Release factors
4. AUG codon
5. Dissociation of ribosomes

**Core Concept:**
The process of translation in eukaryotic cells involves the synthesis of proteins from mRNA molecules. The hydrolytic step refers to the release of the newly synthesized polypeptide chain from the ribosomes, which occurs at the ribosome's exit tunnel. This is crucial for the maturation of the proteins and their subsequent function within the cell.

**Why the Correct Answer is Right:**
The hydrolytic step involves the release of the polypeptide chain from the ribosomes. This process is catalysed by release factors, which interact with the ribosome and the mRNA, recognizing the stop codon (UAA, UAG, or UGA) and facilitating the hydrolysis of the peptide bond between the last amino acid and the tRNA molecule. This allows the polypeptide chain to be released from the ribosome and continue with its folding and maturation.

**Why Each Wrong Option is Incorrect:**

A. Stop codons: Stop codons are the key components that signal the end of translation, but they cannot catalyze the hydrolysis of the peptide bond.
B. Peptidyl transpeptidase: This enzyme is responsible for peptide bond formation during translation, not its hydrolysis.
C. AUG codon: AUG (methionine) codon represents the start codon, initiating protein synthesis, not its termination.
D. Dissociation of ribosomes: Dissociation of ribosomes would lead to termination of translation, not the hydrolysis of the peptide bond.

**Core Concepts:**
1. Translation is a process in which ribosomes synthesize proteins from mRNA molecules.
2. The hydrolytic step, catalyzed by release factors, is crucial for the maturation and function of the newly synthesized polypeptide chain.

**Clinical Pearls:**
1. Understanding the correct pathways involved in translation and hydrolysis helps to comprehend the functioning of cells and the synthesis of proteins.
2. Knowledge of the correct answer can assist in interpreting protein synthesis assays in clinical diagnostics and drug development.