Mitosis and Cytokinesis Mr. Fuchigami Thursday, April 12th, 2018

What is mitosis? Mitosis: Phase in the cell cycle in which the genetic material (DNA) is divided and two genetically identical daughter cells are produced. Occurs for somatic cells. There are 4 main stages in mitosis: Prophase Metaphase Anaphase Telophase PMAT

Early Interphase DNA exists in the cell’s nucleus as chromatin (relaxed, messy form). Before DNA replication (S phase of cell cycle).

Late Interphase After DNA replication (S phase of cell cycle). Two copies of the genetic material are present in the nucleus. Chromatin begins to condense into chromosomes. Homologous chromosomes (1 chromosome from mom; 1 chromosome from dad) are present.

Prophase Chromatin tightens into chromosomes. Spindle fibres form in the cytoplasm. They attach to the centromere of the chromosomes. Nuclear membrane breaks down.

Metaphase Chromosomes line up at the center of the cell. Forms metaphase plate.

Anaphase Spindle fibres pull on centromeres and sister chromatids move to opposite sides of the cell.

Telophase Chromosomes reach opposite sides of the cell. New nuclear membranes form around the chromosomes. Chromosomes relax to form chromatin. Spindle fibers disappear.

Cytokinesis Cytoplasm divides and cell membranes pinch inward until the cell divides in two. Two identical daughter cells are produced.