The Stages of Mitosis Ch. 8

Mitosis is… The division of the nucleus! Mitosis only deals with the Cell division is the rest of the cell cytokinesis = cytoplasm

Prophase The 1st phase of mitosis Coiling of DNA into chromosomes The 2 copies of each chromosome – the chromatids- stay connected to one another by the centromere. Centrioles

Centrioles in Prophase 2 pairs centrosomes appear near the nucleus Each centrosome contains a pair of small, cylinders (pasta looking) things called centrioles The centrosomes of plant cells lack centrioles. In both animal and plant cells the centrosomes move toward opposite poles of the cell

Prophase Continued As centrosomes separate, spindle fibers made of microtubules radiate from the centrosomes The array of spindle fibers is called the mitotic spindle which will equally divide the chromatids between the two daughter cells

Metaphase 2nd phase of mitosis Chromosomes are easy to identify in microscope because they are lined up and dense Microtubules line chromosomes at center of the cell

Anaphase 3rd phase of mitosis The chromatids of each chromosome separate at the centromere They move, centromere first, toward opposite poles of the dividing cell. After the chormatids separate, they are considered to be individual chromosomes

Telophase 4th phase of mitosis Once chromosomes reach opposite ends of the cell, the spindle fibers disassemble (break apart) The chromosomes return to their loose state and the nuclear envelope forms around each set of chromosomes