What statement best describes the Central Dogma of molecular biology?

• A. DNA replicates; transcription makes mRNA; translation uses mRNA to synthesize protein; information flows 5' to 3'.
• B. Protein synthesis precedes transcription.
• C. RNA is the information storage, transcribed into DNA.
• D. Proteins are directly synthesized from DNA without RNA.

Answer: (A)

The key idea being tested is how genetic information is transferred in organisms: DNA is replicated, transcribed into RNA, and RNA is translated into protein, with the information typically flowing from DNA to RNA to protein. The best statement captures all three steps and the directionality: DNA serves as the template for making mRNA, which then guides the synthesis of a protein, and this flow occurs in a 5' to 3' direction. This contrasts with ideas that place protein synthesis before transcription, that RNA is the storage form of genetic information, or that proteins are made directly from DNA without RNA intermediates. The inclusion of DNA replication and transcription-to-translation wiring reflects how genetic information is preserved and expressed in cells.