Final answer:
Ribosomes are made up of rRNA and proteins, and not mRNA, tRNA, DNA, or proteins alone. rRNA has an enzymatic role in catalyzing peptide bond formation during protein synthesis.
Step-by-step explanation:
Ribosomes are essential cellular components responsible for protein synthesis. They are composed of ribosomal RNA (rRNA) and proteins, making option B) rRNA and proteins the correct answer to the question. Each ribosome consists of two subunits: a large one and a small one. The rRNA within the ribosome ensures proper alignment of the messenger RNA (mRNA), transfer RNA (tRNA), and ribosomes. It also possesses enzymatic activity, specifically peptidyl transferase, which catalyzes the formation of peptide bonds during protein synthesis. The mRNA is read in codons, each coding for a single amino acid, and the tRNA carries the corresponding amino acid to be added to the growing polypeptide chain.