GENETICS

Mitosis and the Cell Cycle Cell reproduction

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.

Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm As you can see Mitosis is a continuous cycle and does not stop at each phase like shown in the picture.

The Cell Cycle The sequence of growth and division of a cell. 95% of cell cycle in interphase 5% of cell cycle in mitosis

Interphase Growth Stage 1 (G1) – metabolic activity of the cell Synthesis Stage (S) – metabolic activity of the cell, replication of DNA Growth Stage 2 (G2) – metabolic activity of the cell, prepare for division

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

MITOSIS There are PROPHASE four phases METAPHASE of mitosis. ANAPHASE TELOPHASE

Prophase Nuclear membrane fades Chromosomes condense – can see sister chromatids and centromere Spindle forms Centrioles start to move to opposite poles

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

Metaphase Chromosomes line up along the equator (middle) of the cell Each chromatid is attached to spindle with centromere

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

Anaphase Centromeres divide Sister chromatids are pulled apart to opposite poles of the cell Each chromatid is now a separate chromosome

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

Telophase Spindle fibers dissolve Chromosomes reach the opposite poles and begin to uncoil (lengthen) Nuclear envelopes (2) reform

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

Cytokinesis Cytoplasm divides Two new daughter cells are now separate

Animal Mitosis -- Review Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase                                                             

Plant Mitosis -- Review Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase