What is the central dogma of molecular biology?

• A. DNA is transcribed into RNA, which is translated into protein.
• B. RNA is transcribed into DNA, which is translated into protein.
• C. Protein is transcribed into RNA, which is translated into DNA.
• D. DNA is replicated into RNA, which becomes protein.

Answer: (A)

Genetic information flows from DNA to RNA to protein. In transcription, a gene’s DNA sequence is used as a template to synthesize RNA. In translation, the information carried by that RNA is read to assemble amino acids into a protein, with the RNA sequence dictating the order of amino acids. This pathway explains how the genetic code in DNA ultimately determines the proteins that carry out cellular functions. DNA replication is a separate process that copies DNA for cell division, not a step in the flow of information to proteins. The other options misstate the direction or the molecules involved (for example, RNA to DNA, or protein to RNA, or DNA to RNA via replication), so they don’t reflect how genetic information normally moves in cells.