What role does mRNA play in protein synthesis?

mRNA, or messenger RNA, serves a critical role in the process of protein synthesis by carrying the genetic instructions from DNA to the ribosome. In eukaryotic cells, the process begins in the nucleus where DNA is transcribed into mRNA. This mRNA molecule then exits the nucleus and enters the cytoplasm, where ribosomes, the cellular machinery for protein synthesis, are located.

Once in the cytoplasm, the ribosome reads the sequence of codons (three-nucleotide sequences) on the mRNA. Each codon corresponds to a specific amino acid, which are the building blocks of proteins. The ribosome uses this information to facilitate the assembly of amino acids into a polypeptide chain, ultimately folding into a functional protein.

This fundamental role of mRNA highlights its importance in translating the genetic code into functional proteins, a crucial process for cell structure and function. The other options all describe different components or aspects of the protein synthesis process but do not accurately reflect the primary function of mRNA itself.