The anticodon loop of tRNA contains bases that are complementary to the codon. The tRNA molecule plays a crucial role in protein synthesis by transferring amino acids to the growing polypeptide chain on the ribosome. The anticodon loop is one of the essential structures in tRNA that allows it to recognize and bind to the appropriate codon on the mRNA during translation.

Structure of tRNA:
tRNA, or transfer RNA, is a small RNA molecule consisting of about 70-90 nucleotides. It has a cloverleaf-like structure with several important regions, including the anticodon loop. The anticodon loop is located at one end of the tRNA molecule and contains three nucleotides that are complementary to the codon on the mRNA.

Complementary Base Pairing:
The genetic code is translated from the language of nucleotides to the language of amino acids through a process called translation. During translation, the mRNA molecule is read by the ribosome in groups of three nucleotides called codons. Each codon on the mRNA corresponds to a specific amino acid.

The anticodon loop of tRNA is responsible for recognizing and binding to the codon on the mRNA. The bases in the anticodon loop form complementary base pairs with the bases of the codon in the mRNA. For example, if the codon on the mRNA is 'AUG,' the anticodon on the tRNA molecule would be 'UAC' (following the rules of complementary base pairing: A pairs with U, G pairs with C).

Importance of Complementary Base Pairing:
Complementary base pairing between the anticodon loop and the codon ensures the accurate translation of the genetic code. The specificity of base pairing allows the tRNA to selectively bind to the codon that corresponds to the specific amino acid it carries. This ensures that the correct amino acid is added to the growing polypeptide chain during protein synthesis.

Conclusion:
In summary, the anticodon loop of tRNA contains bases that are complementary to the codon on the mRNA. This complementary base pairing is essential for the accurate translation of the genetic code during protein synthesis. The specificity of the interaction between the anticodon and the codon ensures that the correct amino acid is added to the growing polypeptide chain, resulting in the synthesis of functional proteins.