Mitosis Asexual Reproduction Mitosis is the process in

Mitosis Asexual Reproduction Mitosis is the process in which the nucleus divides to form two new nuclei. 1 1

How do little elephants grow up to be BIG elephants? Cell divides …mitosis

Why do animals shed their skin? Dead skin is inadequate to accommodate growing body

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

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.

The Mitosis Cycle • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis http: //www. cellsalive. com/mitosis. htm (see an animated version)

The Phases of Cell Cycle Mitosis Is Only A Small Fraction Of The Entire Cell Cycle The interphase is much larger and is is further divided into G 1, S and G 2 phases

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

Interphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Prophase 1 st step in 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. • Sister chromatids Centrioles Spindle fibers

Prophase Animal Cell Plant Cell Spindle fibers Centrioles Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Metaphase 2 nd step in Mitosis • Chromatids (or pairs of chromosomes) attach to the spindle fibers and allign at the center of the cell called metaphase plate. Centrioles Spindle fibers

Metaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Metaphase Chromosomes are best seen in metaphase as they are most condensed in this phase. Karyotyping is done with metaphase chromosomes

Karyotyping is the process of takin photographs of chromosomes in order to determine the number of chromosomes and any abnormalities. The term is also used for the complete set of chromosomes in a species or in an individual Karyogram of human male

Anaphase 3 rd step in Mitosis • Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers Anaphase is characterized by movement of the chromatids towards the opposite poles

Anaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Telophase 4 th and last step in Mitosis Two new nuclei form. • Chromosomes appear as chromatin (threads rather than rods). (due to decondensation) • Mitosis ends. • Nuclei Chromatin Nuclei

Telophase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/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 cytokinesis

Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Cell Cycle 24

u o n a h T Y k Please see Mitosis Animation http: //www. cellsalive. com/mitosis. htm