Which tRNA anticodon(s) could decode the mRNA codon CAG (recall that codons are always written in the 5'—>3' direction and anticodons are written in the 3'—>5' direction)? A. CUG or GUCB. GUC onlyC. CUG onlyD. GUU or GUC

B. GUC only

Explanation:

Transfer RNA (tRNA) is a special type of RNA molecule that plays a vital role during translation. It matches an mRNA codon with its corresponding amino acid. The tRNA does this through a set of three nucleotide sequences called ANTICODON, that it contains.

The tRNA reads the mRNA codon using its anticodon, which is complementary to the mRNA codon. The reading is done following the complementary base pairing rule i.e. A-U and C-G.

Hence, a mRNA codon with nucleotides CAG will be read by a tRNA codon with GUC nuceleotide, which is complementary to it. Note that, the complementarity of the anticodon sequence makes it oriented in the 3'-5' direction.