Question

Which codon does not have tRNA?

• A. Start codon
• B. Stop codon
• C. AUG
• D. GGG
• E. UUU

Answer 1

The correct option is B Stop codon

A. Start codon is AUG. Since AUG also codes for methionine, it has a tRNA molecule carrying methionine in eukaryotes and formylated methionine in prokaryotes.

B. There are three stop codons UAA, UAG, UGA. These do not code for any amino acid. Hence, they do not have tRNA molecules.

C. AUG codes for methionine. Hence, it has tRNA molecule carrying methionine.

D. GGG codes for glycine and has a tRNA molecule carrying glycine.

E. UUU codes for phenylalanine and has a tRNA molecule carrying phenylalanine.

So, the correct answer is 'Stop codon'.