Question

The number of release factors identified in prokaryotes is
A. 2
B. 3
C. 7
D. 9

Answer 1

Release factors are a protein meant for termination of the process of translation by recognizing codon i.e. the termination codon or the stop codon in the mRNA sequence. These release factors are very important in archaea, prokaryotes, and eukaryotes.

Step by step answer: The release factors are very important in the protein formation i.e., in the process of translation. These release factors show their importance as they help in the release of new peptides. These release factors are required, tRNAs do not usually recognize the stop codon, therefore, they require protein which was named release factor. It was demonstrated that different release factors recognize different stop codons.
There are two classes of release factors:
-Class 1 release factors- these class 1 factors have the most important function they bind to the A site of the ribosome in a way of mimicking tRNA which releases new peptides as it causes the ribosome to disassemble. Prokaryotic class 1 release factors include RF1 and RF2. RF1 is meant to recognize UAA and UAG stop codons while RF2 is meant to recognize UAA and UGA stop codons. Eukaryotic class 1 release factor includes only a single release factor I.e. eRF1 release factor that is meant for all three of the stop codons. Archaeal class 1 release factor is aRF1 and it all recognizes all three stop codons. The close similarity in the function between the eukaryotic and prokaryotic release factors suggests that structure may be similar but there may be a change in some amino acids.
-Class 2 release factors- it includes GTPases and its main function is to dissociate class 1 release factor from the ribosome. Also, this enhances the function of class 1 release factors. These release factors are evolutionary linked.
Hence option A is correct.

Note: Release factors as such are very important in the process of translation recognizing the site and making possible the formation of new peptides by attaching themselves to an appropriate stop codon.