Question

Which of the following groups of codons are used for the termination of polypeptide chain synthesis?

Options

• AUA, GAU, UGA

• AAU, GAU, GUA

• AUA, AGU, UAA

• UAA, UAG, UGA

Answer 1

UAA, UAG, UGA

Explanation:

The codons UAA, UAG, and UGA are known as stop codons, or termination codons, because they do not encode any amino acid. When a ribosome encounters one of these three sequences on an mRNA strand, it signals the end of translation. Since no tRNA molecules have anticodons to match these triplets, specific proteins called release factors bind to the ribosome instead, causing the newly formed polypeptide chain to be released.