How do little elephants grow up to be BIG elephants? Bell Ringer #24 9/20/18 How do little elephants grow up to be BIG elephants?
Opening: Pancakes!!! I don’t have enough batter to make pancakes for everyone. What if I add some more water to the batter? What if I add some water AND another egg?
Opening: Pancakes (cont.) If a cell is going to divide, creating two “daughter” cells that are identical, what must first happen in the “parent” cell?
The process of asexual reproduction begins after a sperm fertilizes an egg.
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.
Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm 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
Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase 1st 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 2nd 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 3rd 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 4th 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
Why do animals shed their skin?
Closing: Dear Absent Student Pretend one of your friends from this class was absent today. Write him/her a letter that summarizes what we talked about in class today. Your letter should be at least ONE paragraph long!
Bell Ringer #9/10 12/7/16 What would happen if cytokinesis occurred without mitosis?
Opening: Mitosis Video Clip https://www.youtube.com/watch?v=C6hn3sA0ip0
Work Session: Modeling Mitosis Using your kits, model the cell division process of mitosis.
Closing: What’s wrong with this picture? Interphase
Bell Ringer #10/11 12/8/16 Draw what happens during Metaphase in mitosis.
Opening: Meiosis https://www.youtube.com/watch?v=toWK0fIyFlY
Work Session: Directed Reading Read p. 126-132 Answer Directed Reading questions on a SEPARATE sheet of paper.
Closing: Think-Pair-Share How are mitosis and meiosis different and/or similar?