Mitosis

Mitosis  The process of cell reproduction  It is the basis for growth and tissue repair Takes place in regular body cells (somatic cells) Takes place in regular body cells (somatic cells)  The physical division of one parent cell into two daughter cells Parent cell provides each daughter cell with enough DNA (hereditary information) and cytoplasm (and organelles) to properly function on their own Parent cell provides each daughter cell with enough DNA (hereditary information) and cytoplasm (and organelles) to properly function on their own

From one to Two

The Cell Cycle  Each cell undergoes a “regular” cell cycle, that starts from the moment they are created  The cycle is mostly made up of the phase: interphase Dedicated to normal cell functions, and cell growth and DNA replication in preparation for mitosis Dedicated to normal cell functions, and cell growth and DNA replication in preparation for mitosis  Mitosis only plays a small part

Phases of the Cell Cycle  Interphase  Prophase  Metaphase  Anaphase  Telophase  Cytokinesis Mitosis

Interphase  Longest stage in a cells life  Time spent between divisions  Preparation for division Replication of all the necessary materials Replication of all the necessary materials

Interphase 3 phases of Interphase G1: Growth phase (duplication of cell contents, excluding chromosomes) G1: Growth phase (duplication of cell contents, excluding chromosomes) S: Synthesis phase (duplication of each of the 46 chromosomes) S: Synthesis phase (duplication of each of the 46 chromosomes) G2: Check phase (cell checks the duplicated chromosomes for errors before proceeding to division) G2: Check phase (cell checks the duplicated chromosomes for errors before proceeding to division)

Chromosomes

Mitosis: Prophase  First phase 1. The nucleus disappears 2. The nuclear membrane breaks apart 3. The chromosomes become visible The spindle apparatus forms and attaches to the centromeres of the chromosomes

Mitosis: Metaphase  Nuclear membrane now completely gone  Duplicated chromosomes align at the center of the cell (along the cells equator)

Mitosis: Anaphase  The separation of the diploid set of chromosomes (separation of the sister chromatids)  The are pulled to opposite poles of the cell by the spindle fibres

Mitosis: Telophase  Begins when the chromatids arrive at the opposite poles  Nuclear membrane and nucleoli (nucleus) reform  Chromasomes uncondense

Cytokinesis  The cytoplasmic division   The cytoplasm, organelles, and nuclear material are evenly split and two new cells are formed.  Cleavage of the cell

Final Product  At the end of mitosis, the two products are called daughter cells. They are identical, each with 46 chromosomes