Multiple choice

Which of the following amino acids is incorporated into protein by codon namely UGA?

  1. Cysteine

  2. Cystine

  3. Selenocysteine

  4. Alanine

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

UGA is normally a stop codon, but in the presence of a SECIS element and specialized translation machinery, it codes for selenocysteine, the 21st proteinogenic amino acid. Selenocysteine contains selenium instead of sulfur.