The main difference between tRNA and mRNA is the presence of an anticodon in tRNA. The anticodon is a sequence of three nucleotides on tRNA, which is complementary to a specific codon, which is a sequence of three nucleotides on mRNA. The anticodon in tRNA is responsible for recognizing and binding to the complementary codon on mRNA during protein synthesis. tRNA brings the correct amino acid to the mRNA complex by recognizing the three nucleotides and attaching the matching amino acid to the correct position in the protein.