What is the role of mRNA in protein synthesis?

The role of mRNA, or messenger RNA, in protein synthesis is fundamentally to carry genetic information from DNA to the ribosome. This process begins when the DNA in the nucleus is transcribed into mRNA, which then exits the nucleus and enters the cytoplasm. The mRNA serves as a template during translation, where ribosomes read the sequence of codons (three-nucleotide sequences) on the mRNA to assemble the corresponding amino acids into a polypeptide chain, ultimately forming a protein.

The other roles listed do not accurately describe the function of mRNA in protein synthesis. For instance, mRNA does not synthesize proteins; this process occurs at the ribosome. Additionally, while ribosomes are indeed made up of ribosomal RNA (rRNA) and proteins, mRNA does not serve as a structural component of ribosomes. Finally, mRNA does not modify or process proteins; rather, that role is typically associated with other types of RNA and cellular mechanisms that occur after translation. Therefore, the correct understanding of mRNA’s role highlights its critical function as the carrier of genetic information necessary for protein synthesis.