--- title: "Genome — AP Biology Definition & Exam Guide" description: "The genome is an organism's complete set of DNA, and mitosis copies it perfectly into two daughter cells. Learn how it shows up on the AP Bio exam." canonical: "https://fiveable.me/ap-bio/key-terms/genome" type: "key-term" subject: "AP Biology" unit: "Unit 4" --- # Genome — AP Biology Definition & Exam Guide ## Definition In AP Biology, the genome is the complete set of genetic material (DNA) in an organism, including all its genes and regulatory sequences. Mitosis passes a full, identical copy of the genome to each new daughter cell. ## What It Is The genome is everything written in an organism's DNA: every gene, plus the [regulatory sequences](/ap-bio/key-terms/regulatory-sequences "fv-autolink") that control when those genes turn on and off. Think of it as the full instruction manual for building and running the cell. Nothing gets left out when we say "genome" because it means the whole set, not just one chapter. In the [cell cycle](/ap-bio/unit-4/homeostasis-feedback-loops/study-guide/OgMSpwCrEez0qyWtlCAC "fv-autolink") (topic 4.5), the genome is the thing that has to be copied and shared. During S phase, DNA replicates so each chromosome becomes two identical sister chromatids joined at a centromere. Then mitosis splits those copies apart so two [daughter cells](/ap-bio/unit-5/meiosis/study-guide/FC0aTuODYikjJuhlBO1Z "fv-autolink") each end up with a complete, identical genome. That's the whole point of mitosis: make one full copy, then hand a full copy to each new cell. ## Why It Matters Genome lives in [Unit 4](/ap-bio/unit-4 "fv-autolink") (Cell Communication and Cell Cycle), specifically topic 4.5. It anchors learning objective [AP Bio](/ap-bio "fv-autolink") 4.5.B, which asks you to explain how mitosis transmits chromosomes from one cell generation to the next. The essential knowledge states it directly: mitosis ensures the transfer of a complete genome from a parent cell to two genetically identical daughter cells. So when you describe growth, tissue repair, or asexual reproduction, the genome is what's being faithfully duplicated and distributed. It also ties to AP Bio 4.5.A, since S phase is where the genome physically gets copied. ## Connections ### Mitosis and Genetically Identical Daughter Cells (Unit 4) [Mitosis](/ap-bio/key-terms/mitosis "fv-autolink") exists to hand each daughter cell a complete, identical genome. That's why skin cells replacing damaged tissue are genetic copies of the original, no shuffling, no loss. ### Chromosomes, Chromatin, and Sister Chromatids (Unit 4) The genome isn't loose DNA floating around. It's packaged as [chromatin](/ap-bio/key-terms/chromatin "fv-autolink"), condensed into chromosomes during division, and copied into paired sister chromatids during S phase. Same information, different packaging at different stages. ### Mitochondrial DNA and Phylogenetics (Units 4, 7) A 2018 FRQ used [mitochondrial DNA](/ap-bio/key-terms/mitochondrial-dna "fv-autolink") sequences to compare bear populations. That's the genome (or a piece of it) being read as an evolutionary record, linking the molecule you copy in mitosis to the bigger story of relatedness and speciation. ## On the AP Exam Multiple-choice stems often describe a cell dividing and giving each daughter cell a full set of DNA, then ask you to name that complete set. The answer is the genome. You'll also see questions contrasting interphase (where the genome gets duplicated in S phase) with mitosis (where it gets split). On FRQs, the genome shows up two ways: directly, as the thing mitosis transmits intact, and indirectly, as DNA sequence data used in evolution questions like the 2018 phylogenetic-tree FRQ comparing bear mitochondrial DNA. Be ready to explain WHY both daughter cells are genetically identical, the copying in S phase plus the even split in anaphase guarantees each gets a complete genome. ## genome vs chromosome A genome is the entire set of DNA in an organism. A chromosome is one packaged piece of that DNA. Humans have one genome but 46 chromosomes. So the genome is the whole library; a chromosome is a single volume on the shelf. ## Key Takeaways - The genome is an organism's complete set of DNA, including every gene and all regulatory sequences. - Mitosis transmits a complete, identical genome to each of the two daughter cells (AP Bio 4.5.B). - The genome physically gets copied during S phase, forming sister chromatids joined at the centromere. - Because of that copying and the even split in anaphase, daughter cells from mitosis are genetically identical. - A genome is the whole set of DNA; a chromosome is one packaged piece of it. ## FAQs ### What is a genome in AP Biology? It's the complete set of genetic material (DNA) in an organism, covering all genes and regulatory sequences. On the AP exam, it most often appears as the full set of DNA that mitosis copies and passes to each daughter cell. ### Is a genome the same as a chromosome? No. The genome is the entire set of DNA in an organism, while a chromosome is just one packaged piece of that DNA. Humans have one genome split across 46 chromosomes. ### How does mitosis keep the genome the same in both daughter cells? The genome is duplicated during S phase into identical sister chromatids, then anaphase pulls one copy of each chromosome to opposite ends. Each daughter cell ends up with a complete, identical genome, which is why they're genetically identical. ### Is genome on the AP Bio exam? Yes. It's part of topic 4.5 (Cell Cycle) in Unit 4 and supports learning objective AP Bio 4.5.B. It also appears in evolution questions, like the 2018 FRQ that used mitochondrial DNA sequences to compare bear populations. ### When does the genome get copied during the cell cycle? During S phase of interphase, before mitosis begins. The DNA replicates so each chromosome becomes two sister chromatids connected at a centromere, ready to be split evenly in mitosis. ## Related Study Guides - [4.5 Cell Cycle](/ap-bio/unit-4/homeostasis-feedback-loops/study-guide/OgMSpwCrEez0qyWtlCAC) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/ap-bio/key-terms/genome#resource","name":"Genome — AP Biology Definition & Exam Guide","url":"https://fiveable.me/ap-bio/key-terms/genome","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/ap-bio/key-terms/genome#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-06-11T05:27:39.110Z","isPartOf":{"@type":"Collection","name":"AP Biology Key Terms","url":"https://fiveable.me/ap-bio/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/ap-bio/key-terms/genome#term","name":"genome","description":"In AP Biology, the genome is the complete set of genetic material (DNA) in an organism, including all its genes and regulatory sequences. 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