Mitosis

Somatic cells

• Most of the body's cells • Diploid (2n) : 46 chromosomes

Reproductive cells: gametes

• Sperm and egg cells • Haploid (1n): 23 chromosomes

Interphase

• Cell doubles in size and DNA during interphase • 90-95% of cell cycle • G1: cell grows without replicating DNA • S: synthesis phase, DNA replicates • G2: cell synthesizes proteins in preparation for mitosis • Chromosomes condensed during mitosis: uncondensed (chromatin form) for rest of cell cycle

mitosis

Somatic cell division

Prophase

• Centrosomes migrate to opposite sides of cell • Mitotic spindles form from centrosomes

Prometaphase

• Nuclear envelope fragments • Nucleolus disappears • Sister chromatids attached to each other at their centromeres until anaphase

Metaphase

• Chromosomes line up at metaphase plate

Anaphase

• Sister chromatids move to opposite sides of cell

Telophase

• Nuclear envelope reforms

Cytokinesis

• Cytoplasm divides cell into two • Produces 2 diploid daughter cells with identical genomes

Mitosis

• Division of nucleus into 2 daughter nuclei

Cytokinesis

• Division of cytoplasm

CLINICAL CORRELATION

Aneuploidy

• Sister chromatids do not separate properly during cell division (mostly meiosis but also occurs during mitosis) • Daughter cells with extra or missing chromosome • Common in cancer cells

Mitosis

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