Final answer:
The sequence on transfer RNA that is complementary to the codon on mRNA is called the anticodon.
Step-by-step explanation:
Each transfer RNA (tRNA) has a sequence called the anticodon that is complementary to the codon on the messenger RNA (mRNA) molecule. The anticodon plays a crucial role in translating the language of RNA into proteins during translation. The tRNA anticodon pairs with the mRNA codon, ensuring that the correct amino acid is added to the growing polypeptide chain.