Genetic information in a cell flows in one general, predictable direction: from DNA, which stores the information long-term, to RNA, which carries a working copy of a specific instruction, to protein, which actually carries out the resulting function. This directional flow is foundational enough to molecular biology that it's known as the central dogma — a name coined by Francis Crick, one of the co-discoverers of DNA's structure, that has stuck for decades despite Crick himself later admitting he'd chosen a word, "dogma," whose actual meaning he hadn't fully appreciated when he picked it.
DNA to RNA to protein, and generally not the other way
The central dogma describes genetic information moving from DNA (the stored, stable master copy) to RNA (a working, disposable copy of a specific instruction, produced through a process called transcription) to protein (the functional molecule that copy's instructions actually build, produced through a process called translation). Crucially, the dogma as originally framed held that this information flow runs in essentially one direction: sequence information moves from nucleic acid to protein, not from protein back into nucleic acid, and information generally doesn't flow "backward" from protein to nucleic acid at all. This one-directional framework gave molecular biology a clear, foundational organising principle for how genetic information actually gets used inside a living cell.
A word Crick later said he picked without knowing what it meant
Crick later wrote, in his own retrospective account, that he'd chosen the word "dogma" simply because it sounded suitably important and central, without originally appreciating that the word's more precise meaning implies an idea accepted as true without question or evidence — precisely the opposite of how scientific principles, including this one, are actually meant to be treated, as claims held provisionally and open to revision if solid contrary evidence emerges. That naming choice has occasionally created genuine confusion, since discoveries after Crick's original 1958 formulation — including reverse transcription, in which certain viruses do copy RNA information back into DNA — required refining the details of the original framework, refinements Crick himself argued were fully consistent with what he'd actually meant by the central dogma's core claim all along, even though the popular, simplified version of the idea that had spread more widely didn't always capture that same nuance.
What we're still unsure about
The core directional flow of genetic information from DNA to RNA to protein, and the existence of exceptions like reverse transcription in certain viruses, are extremely well established molecular biology, confirmed through decades of subsequent research. What's more a matter of historical and semantic nuance than open science is exactly how Crick's original 1958 formulation of the central dogma should be interpreted relative to the more simplified, popularised version that later became widely taught — Crick argued discoveries like reverse transcription didn't actually violate his original, more carefully worded claim, but that careful original wording isn't always what gets conveyed in shorter, more simplified textbook summaries, a genuine, still-debated gap between the precise original formulation and its popular shorthand.
This sits inside Nucleic Acids & the Central Dogma, one of seven topics in Biochemistry, one of six domains in Chemistry, one of seventeen subjects the app can quiz you on.