What function does rRNA serve in the cell?

Ribosomal RNA (rRNA) plays a crucial role as a structural component of ribosomes, which are essential cellular machinery responsible for protein synthesis. Ribosomes are made up of rRNA and proteins, and the rRNA provides a scaffold that allows the ribosomal proteins to associate and form the functional ribosome.

In the process of protein synthesis, rRNA not only provides structure but also has catalytic functions, especially in the formation of peptide bonds between amino acids during translation. This integral role of rRNA in both the structural and functional aspects of ribosomes underpins its designation as a critical component of the protein synthesis machinery.

The other choices relate to different roles in the cell: amino acids are carried by transfer RNA (tRNA), the template for protein synthesis is messenger RNA (mRNA), and intron splicing is facilitated by small nuclear RNA (snRNA) and the spliceosome. Therefore, the specificity of rRNA's function as a structural component of ribosomes makes it the correct answer in this context.