Which type of RNA is involved in forming the structure of ribosomes?

Ribosomal RNA (rRNA) is critical in the formation and structure of ribosomes, which are the cellular machinery responsible for protein synthesis. rRNA combines with proteins to create the ribosome's two subunits: the large and the small subunit. This combination is essential for the ribosome's function, as rRNA helps maintain the ribosome's shape and plays a key role in catalyzing the peptide bond formation between amino acids during translation.

While messenger RNA (mRNA) serves as the template for the sequence of amino acids in a protein and transfer RNA (tRNA) carries amino acids to the ribosome for protein synthesis, neither of these types of RNA contributes to the physical structure of the ribosome itself. Complementary DNA (cDNA) is a form of DNA synthesized from messenger RNA, and it is not involved in the structure of ribosomes at all. Therefore, the role of rRNA in forming the ribosome is crucial for the entire process of translating genetic information into functional proteins.