What is the role of tRNA in protein synthesis?

• A. Catalyzes reactions
• B. Transfers amino acids to the growing polypeptide chain
• C. Modifies RNA strands
• D. Replicates DNA

Answer: (B)

tRNA, or transfer RNA, plays a crucial role in protein synthesis by transferring amino acids to the growing polypeptide chain during translation, which is the process of assembling proteins based on the genetic code carried by mRNA (messenger RNA). Each tRNA molecule is specific to one amino acid and carries it to the ribosome where translation occurs. The tRNA recognizes the corresponding codon on the mRNA through its anticodon, ensuring that the correct amino acid is added in the appropriate sequence to form a functional protein.

This process is vital because the sequence of amino acids determines the structure and function of the protein being synthesized, which in turn affects various biological processes within the organism. The other options do not accurately represent the function of tRNA: it does not catalyze reactions (that role is more associated with ribozymes and enzymes), it does not modify RNA strands (which is done by other RNA processing mechanisms), and it does not replicate DNA (a function performed by DNA polymerase and other proteins involved in DNA replication). Thus, the correct answer reflects the specific and essential role of tRNA in the translation phase of protein synthesis.