Cell and nuclear division coordinate DNA replication, chromosome movement, cytokinesis, meiosis, cell-cycle control and proliferation to produce new cells in organisms.
Coverage 2010–2025 · Updated 16 Jul 2026
• All cells arise from pre-existing parent cells by cell division
• Division produces daughter cells for growth, replacement, repair, or reproduction
• Cytokinesis splits cytoplasm after nuclear division
• Animal cells use a contractile ring; plant cells form a vesicle-derived cell plate
• Equal cytokinesis gives daughter cells similar amounts of cytoplasm
• Unequal cytokinesis occurs in oogenesis and yeast budding
• Mitosis maintains chromosome number for growth, repair, and asexual reproduction
• Meiosis halves chromosome number for gametes and generates genetic diversity
• DNA replication in interphase produces chromosomes with sister chromatids
• Sister chromatids remain joined at centromeres until separation
• Mitosis and meiosis both condense chromatin into movable chromosomes
• Histones, nucleosomes, spindle microtubules, and motor proteins organize movement
• Prophase condenses chromosomes; metaphase aligns them at the equator
• Anaphase separates chromatids; telophase reforms nuclei, producing identical nuclei
• Mitosis phases are identified in diagrams, micrographs, and root-tip squashes
• Chromosome condensation, equator alignment, separation, and nuclear membranes are cues
• Meiosis has two nuclear divisions after one round of DNA replication
• Homologous chromosomes separate in meiosis I, producing haploid nuclei
• Non-disjunction is failed separation of homologues or sister chromatids in meiosis
• Down syndrome usually results from trisomy 21 after non-disjunction
• Crossing over at chiasmata exchanges DNA between non-sister chromatids
• Random orientation of bivalents and fertilization create new allele combinations
