Cell division is necessary for normal growth, repair, and reproduction of an organism. 2 types of cells somatic cells (body cells) diploid cells - 2 sets of chromosomes (2n) reproductive cells (sperm and egg) haploid cells - single set of chromosomes (n)

Mitosis - process of cell division in which a somatic cell makes an identical copy of itself involves one chromosome replication and 1 cell division 1 parent cell forms 2 identical daughter cells

Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Longest part of the cell cycle No division happens G1 – growth of cell S – (synthesis) DNA is copied

Each identical sister chromatid is joined at the centromere.

G2 – preparation to divide Video Clip

The chromosomes condense into sister chromatids (visible) Centrioles separate and move to opposite

Spindle fibers form between the centrioles Nuclear membrane breaks apart Video Clip

The chromosomes line up along the spindle fibers in the middle of the cell. Video Clip

The sister chromatids separate at the centromeres Chromatids are pulled to opposite ends of the cell by the spindle fibers. Nuclear membrane forms again. Video Clip

Spindle fibers dissolve Nucleus reforms Chromsomes unwind into chromatin. Cell begins to “pinch in” (animal cell) or grow a cell plate (plant cell) Cytokinesis – cytoplasm divides into 2 identical cells Video Clip