What is the primary function of an anticodon?

The primary function of an anticodon is to ensure that the correct amino acids are brought to the growing polypeptide chain during protein synthesis. Anticodons are found on transfer RNA (tRNA) molecules, which play a critical role in translating the information carried by messenger RNA (mRNA) into a specific sequence of amino acids.

Each anticodon is a set of three nucleotides that is complementary to a corresponding codon on the mRNA strand. When the mRNA is being read during translation, the anticodon pairs with its matching codon, allowing the tRNA to deliver the appropriate amino acid to the ribosome. This matching process is essential for building proteins accurately according to the genetic code.

The other options presented in the question describe functions that are not associated with anticodons. Initiating DNA replication is a function related to enzymes and proteins involved in DNA synthesis. Synthesizing ribosomal RNA is a separate process that occurs in the nucleus and is vital for forming ribosomes, but it does not involve anticodons. Regulating gene expression refers to mechanisms that control the timing and amount of gene transcription and translation, which also does not pertain to the role of the anticodon in protein synthesis.