Mitosis!

Mitosis Asexual reproduction is reproduction that occurs when the parent produces offspring without the process of meiosis or and fertilization Sexual reproduction is when genetic material from two different cells combine producing offspring. Mitosis is a form of asexual reproduction the process in which the nucleus divides to form two new nuclei (Click on Mitosis above for video) 2

How do little elephants grow up to be BIG elephants?

Why do animals shed their skin?

Three reasons why cells reproduce by asexual reproduction: 1. Growth 2 Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cell that reproduce by asexual reproduction reproduce constantly.

Genetic Material (DNA) Is found inside the nucleus of the cell Every human body cell has 46 chromosomes (23 from mom, 23 from dad) DNA is copied during interphase (before mitosis starts)

The process of asexual reproduction begins after a sperm fertilizes an egg.

What living things use mitosis? Both plants and animals use mitosis Some unicellular organisms use mitosis to reproduce

Plant and Animal Cells Plant cells have chloroplast (for photosynthesis)-they also have cell walls Plant cells also have large vacuoles to store water Animal cells have no chloroplast or cell wall-contains small vacuoles if any

Temporary Cell Structures in Mitosis Centrioles, spindle fibers, centromeres are all temporary structures in the cell used for mitosis

Sister Chromatids

Centrioles Centrioles move to the opposite ends of the cell and attach to chromosomes by spindle fibers

Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm Cell Division occurs in a series of stages, or phases Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis

Interphase occurs before mitosis begins Chromosomes are copied (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm Centromere-holds together the sister chromatids

Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Prophase 2nd step in Mitosis Mitosis begins (cell begins to divide) Centrioles (or poles) appear and begin to move to opposite end of the cell. Spindle fibers form between the poles. Centrioles Sister chromatids Spindle fibers

Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Metaphase 3rd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers. Centrioles Spindle fibers

Metaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Anaphase 4th step in Mitosis Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers

Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Telophase 5th step in Mitosis Two new nuclei form. Chromosomes appear as chromatin (threads rather than rods). Mitosis ends. Nuclei Nuclei Chromatin

Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Cytokinesis occurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

Animal Mitosis -- Review Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase                                                             

Plant Mitosis -- Review Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase                                                             

Cell Cycle

Mitosis Animation http://www.cellsalive.com/mitosis.htm