What is the primary purpose of RNA?

• A. To carry protein building instructions from DNA in the nucleus to ribosomes in the cytoplasm
• B. To store genetic information in the nucleus
• C. To catalyze DNA replication
• D. To regulate cell division

Answer: (A)

RNA’s main idea is to act as the messenger that carries the genetic instructions from DNA in the nucleus to the ribosomes in the cytoplasm where proteins are built. Information in genes is first transcribed into messenger RNA, which travels to the cytoplasm. There, the ribosome reads the mRNA codons and guiding molecules like tRNA bring the appropriate amino acids to assemble a protein, with rRNA forming part of the ribosome itself. This makes RNA essential for translating genetic information into protein.

Storing genetic information and catalyzing DNA replication are roles of DNA and DNA-processing enzymes, not the primary job of RNA. RNA’s broader regulatory roles exist, but the core function in most contexts is serving as the information conduit for protein synthesis.