Ribosomes are composed of which molecules?

• A. DNA and protein
• B. Lipids and protein
• C. Ribosomal RNA and protein
• D. Carbohydrates and protein

Answer: (C)

Ribosomes are ribonucleoprotein complexes, made from ribosomal RNA (rRNA) and protein. The rRNA molecules provide the core catalytic and structural framework, helping to form the site where peptide bonds are made and guiding the proper alignment of mRNA and tRNAs. Proteins associate with the rRNA to stabilize the ribosome’s structure and assist its assembly and function. Because a ribosome is not built from DNA, lipids, carbohydrates, or a mixture of these alone, the combination of rRNA and protein is what defines its composition.