Question

These factors (1,2, and 3) recognize the stop codon at the A site and release polypeptide from ribosome.

A) Release Factors
B) Initiation Factors
C) Elongation Factors
D) Transcription Factors

Answer 1

The factors which recognize stop codons during the termination phase of protein synthesis and aid in releasing the polypeptide from the ribosome are Release Factors. These factors are essential for catalyzing hydrolysis, releasing the polypeptide, and disassembling the ribosomal subunits to terminate translation.

Step-by-step explanation:

The factors that recognize the stop codon at the A site and release the polypeptide from the ribosome are known as Release Factors (option A). These factors are crucial in the termination stage of translation. Release factors fulfill several functions:

1. They catalyze the hydrolysis of the terminal peptidyl tRNA bond.
2. They facilitate the release of the newly synthesized polypeptide and the last tRNA from the P site.
3. They contribute to the dissociation of the ribosomal complex into its subunits, which effectively terminates the process of protein synthesis.

Since no tRNA matches stop codons (UAA, UAG, or UGA), the ribosome stalls temporarily, allowing a release factor to bind to the A site. This interaction triggers the release of the new polypeptide and the disassembly of the ribosomal subunits from the mRNA.