What is a Stop Codon?
The stop codon is a special termination codon that signals to stop a protein translation process. It disassociates the ribosomal subunits, and thus disrupts the polypeptide chain during translation effectively. The most common recognized stop codons in the genetic code are UAG, UAA, and UGA. These codons are also known as termination codons or nonsense codons as they do not code for an amino acid.
The three STOP codons are named as amber (UAG), opal or umber (UGA) and ochre (UAA). Charles Steinberg and Richard Epstein discovered “Amber” or UAG, and they named it after their friend Harris Bernstein’s last name in German. The remaining two STOP codons were then named “ochre” and “opal” so as to maintain the “color names” theme.
During protein synthesis, Stop codons cause the release of the nascent polypeptide chain from the ribosome. This happens because there exists no tRNAs with anticodons complementary to the Stop codons.
Also Read: Genetic Code And Mutations
Difference between Start Codon and Stop Codon
Start and stop codons are two punctuation marks of the genetic code that signal the beginning and end of protein synthesis. The main difference between the start and stop codon is that the start codon marks the site at which translation into protein sequence begins whereas the stop codon marks the site at which translation ends. The most common start codon is AUG which codes for methionine while there are three stop codons UAG, UAA, and UGA, and they do not code for an amino acid.
Table of Content
- Differences between the Start codon and Stop codon
- What is Genetic code?
- What is a Start Codon?
- What is a Stop Codon?
- Similarities Between Start Codon and Stop Codon
- Conclusion: Difference between Start Codon and Stop Codon