A mutation is a heritable change in a cell's DNA sequence that, through the central dogma of transcription and translation, alters codon reading and therefore protein product; a mutagen is any chemical substance or physical agent that raises the probability of such changes. Mutagens are classified by origin as endogenous (arising within the organism's own metabolism, principally reactive oxygen species generated during oxidative phosphorylation) or exogenous (originating in the external environment, including intercalating agents that distort helical structure and base analogs that mispair after incorporation). A carcinogen is defined by outcome rather than mechanism — any agent that leads to cancer, i.e. uncontrolled cell division and tumor formation — so the sets of mutagens and carcinogens overlap without either containing the other; the topic sits in molecular biology at the junction of DNA damage, gene expression, and oncogenesis.
A mutation is a heritable change in a cell's DNA sequence that, through the central dogma of transcription and translation, alters codon reading and therefore protein product; a mutagen is any chemic…