Mitosis and cytokinesis result in cell division, or the production of two new daughter cells.Mitosis is a cell division or cell cycle process which results in two daughter cells having the same number and kind of chromosomes as the parent cell. Mitosis and cytokinesis result in cell division, or the production of two new daughter cells. MITOSIS

Why is Mitosis Important? Why does it occur? 1. At some point in a cell’s life, it grows to such a size that the processes that go on in the cell become less efficient, the distances too great for the chemical messages to travel, and the cell simply becomes less efficient. 2. New daughter cells are required for growth and repair of cells, reproduction and replacement of dying cells.

Phases of Mitosis 1.Interphase: The longest phase in which the cell is dormant except for the dispersion of chromosomes.Interphase: 2.Prophase: First stage of Mitosis where the chromosomes compact themselves from dispersed chromatin.Prophase: 3.Metaphase: Second stage of Mitosis where the chromosomes line up in the middle of the cell perpendicular to the poles.Metaphase: 4.Anaphase: Third stage of cell division when the chromosomes begin to divide into two sister chromatids and go to opposite ends of the cell.Anaphase: 5.Telophase & Cytokinesis: Final stage where the cytoplasm divides completely in to two, the nuclear envelopes reform, and the nuclei begin to reform resulting in two new cells.Telophase & Cytokinesis:

The period between successive nuclear divisions during which the chromosomes are NOT VISIBLE and the nuclear envelope is intact. 3 things occur 1.During the first part of interphase (G1) the daughter cell gets more energy and becomes larger. 2.After the cells have enough energy and their size is large enough, they go through the S-Phase. In this phase the nuclear material duplicates. 3.Since the S-Phase took so much out of the cell, it has to go through the G2 phase. In this phase the cell becomes large again and receives more energy (like the G1 phase). This energy that is made in G2 is used in cell division of mitosis. Interphase- Stage 1

Back Prophase – Stage 2 Chromatin condenses to form chromosomes. Nucleolus reduced and finally disappears. Nuclear membrane disappears

Prophase (cont’d) Mitotic spindles form; these are also called Astral rays and they connect the centromere to the poles. The Spindles extend from the pole to the equator and are needed to align the chromosomes at metaphase, for pole movement and separation of the daughter nuclei.

Metaphase – Stage 3 The Nuclear envelope breaks down. Spindle moves into nuclear region and vesicles occupy nuclear regionSpindle Chromosomes attach to the spindle and move to the midpoint Chromatids align to opposite polesChromatids

The centromere divides and the chromatids of each chromosome are pulled apart to their respective sides of the spindle.centromerechromatids Anaphase – Stage 4

Telophase- Stage 5 The final stage in mitosis is telophase. The two separated groups of chromosomes (located at opposite ends of the spindle after their separation in anaphase) finally totally pull apart.

Each group of chromosomes forms a nuclear envelope around themselves, creating two new cells. The chromosomes uncoil until they resume the form of random, tangled chromatin (as is in interphase.) The splitting of one cell into two is now complete. chromatin Telophase- Stage 5, cont’d

Cytokinesis This process usually follows directly after mitosis. In animal cells, the cells finally separate by "furrowing" the membrane with an "invisible thread" of action and myosin- separating the two cells. In plant cells, a cell plate forms between the two dividing cells, which will eventually become the two new cell walls. After the process is complete, both daughter cells contain all the properties of a complete, functioning