During which stage of protein synthesis does tRNA play a key role?

tRNA, or transfer RNA, plays a critical role during the translation stage of protein synthesis. In this phase, tRNA serves as the adaptor molecule that translates the genetic code carried by messenger RNA (mRNA) into a specific sequence of amino acids, forming a polypeptide chain. Each tRNA molecule carries a specific amino acid and has an anticodon region that is complementary to the codon on the mRNA strand. This interaction ensures that the correct amino acid is added in the proper sequence, ultimately leading to the synthesis of functional proteins.

In contrast, replication refers to the process of copying DNA, where tRNA is not involved. Transcription is the process of synthesizing RNA from a DNA template, and while RNA is crucial during this stage, it is not tRNA specifically that plays a role. Mutation pertains to changes in the DNA sequence and does not directly involve protein synthesis. Thus, the key involvement of tRNA is uniquely significant within the context of translation.