Codons are present on an mRNA or DNA. They are sequences of three nucleotides that code for a specific amino acid. Anticodons are present on the tRNA (transfer RNA) molecules that help transfer or bring in the amino acids to the mRNA during the translation process. An anticodon also contains a three nucleotide sequence. The nucleotides are complementary to the sequence of nucleotides present on the mRNA being translated, such that the anticodon in the tRNA can interact with the specific codon in the mRNA and thereby bring the specific amino acid being coded for by the mRNA during the translation process.