Transfer RNA (tRNA) is a crucial molecule in protein synthesis, characterized by its cloverleaf structure and function as an adapter that translates mRNA codons into amino acids. Structure of tRNA Primary Structure: tRNA is a single strand of ribonucleotides, typically consisting of 70-90 nucleotides. It contains modified bases that contribute to its stability and function. The primary structure includes several key regions: Acceptor Arm: This end of the tRNA molecule has a CCA sequence at the 3' end, where the corresponding amino acid attaches. Anticodon Arm: Contains the anticodon, a sequence of three nucleotides that pairs with the complementary codon on mRNA during translation. D Arm and TΨC Arm: These regions contain specific modified bases that help in the recognition and binding of tRNA to the ribosome and mRNA. Secondary Structure: The tRNA molecule folds into a cloverleaf shape due to intramolecular base pairing. This structure includes four arms: the acceptor arm, D arm, TΨC arm, and anticodon arm, which are stabilized by hydrogen bonds between complementary bases. Tertiary Structure: The cloverleaf structure further folds into a compact "L" shape, which is essential for its function in the ribosome during protein synthesis. Function of tRNA Amino Acid Transport: tRNA serves as a carrier for specific amino acids, bringing them to the ribosome based on the sequence of codons in the mRNA. Each tRNA molecule is specific to one amino acid, ensuring that proteins are synthesized accurately. Codon-Anticodon Pairing: The anticodon on tRNA pairs with the corresponding codon on mRNA in an antiparallel manner, which is crucial for the correct translation of the genetic code into a polypeptide chain. Peptide Bond Formation: During translation, the ribosome facilitates the formation of peptide bonds between the amino acids brought by tRNA, linking them together to form a growing protein chain. Role in Translation: tRNA moves through the ribosome's A (aminoacyl), P (peptidyl), and E (exit) sites, playing a vital role in the elongation of the polypeptide chain until the entire protein is synthesized. In summary, tRNA is an essential component of the protein synthesis machinery, with a unique structure that allows it to function effectively in translating the genetic code into functional proteins. Its ability to carry amino acids and pair with mRNA codons ensures the accuracy and efficiency of protein synthesis.