Unit 6: Cell Growth and Development 6.4 Mitosis

Mitosis Division of duplicated chromosomes into two new SOMATIC daughter cells.

Prophase: Genetic material inside the nucleus condenses and the duplicated chromosomes become visible. Outside the nucleus, a spindle starts to form. Longest phase of mitosis Chromatin is compacted into visible chromosomes Chromosomes pair up Cell starts to build a spindle (microtubules) that will help separate duplicated chromosomes Nuclear envelope disappears Stage 1 of Mitosis

Metaphase: Centromeres of duplicated chromosomes line-up across the center of the cell. Spindle fibers connect the centromere of each chromosome to the two poles of the spindle Chromosomes line up in the middle (equatorial plane) of the cell Spindle fibers link at centromeres Stage 2 of Mitosis

Anaphase: Chromosomes (chromatids) separate and move along spindle fibers to the opposite end of the cell. Anaphase ends when this movement stops and the chromosomes are in two separate groups. Stage 3 of Mitosis

Telophase: Chromosomes begin to spread into a tangle of chromatin. Nuclear envelope re-forms around two nuclei Spindle breaks apart Nucleolus becomes visible in each daughter cell Stage 4 of Mitosis

Cytokinesis Splits one cell into two, completing the process of cell division. Different in plant and animal cells Animal cells: cell membrane is drawn inward until pinched in two Plant cells: cell plate forms halfway between

Cytokinesis