Section 9-2 : Mitosis & Cytokinesis

Essential Questions What are the events of each stage of mitosis? What is the process of cytokinesis?

How do little elephants grow up to be BIG elephants?

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

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.

Chromosomes Chromosomes are rod-shaped structures made of DNA and protein. Sister Chromatids are identical halves, attached at the center. (at the Centromere) Held together by the Centromere Centromere

Mitosis Cycle Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis

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

Animal Cell Plant Cell Photographs from:

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. Nuclear Membrane disintegrates Chromatin condenses Centrioles Sister chromatids Spindle fibers

Animal Cell Plant Cell Photographs from: Spindle fibers Centrioles

Metaphase “Middle” Chromosomes attach to spindle apparatus. Chromosomes align along equator of cell. (Line up in the middle)

Animal Cell Plant Cell Photographs from:

Anaphase Microtubules shorten, moving pairs of chromosomes to opposite poles. “Away” Centrioles Spindle fibers

Animal Cell Plant Cell Photographs from:

Telophase Chromosomes reach the poles Nuclear envelope reforms Chromosomes De-condense Two new nuclei form. Chromosomes appear as chromatin (threads rather than rods). Mitosis ends. Nuclei Chromatin

Animal Cell Plant Cell Photographs from:

Cytokinesis Animal cells : Cleavage furrow forms, pinches, and divides into 2 daughter cells Plant cells : Cell plate forms, divides daughter cells

Assignment: You will create a foldable book covering the 2 nd main stage of the Cell Cycle, Mitosis, and it’s 4 sub- stages. (Prophase, metaphase, anaphase & Telophase) You will also include the 3 rd main stage of the Cell Cycle, Cytokinesis.

Requirements: Cover Page 1 page per stage of Mitosis - Prophase - Metaphase - Anaphase - Telophase 1 page for Cytokinesis Hand-Drawn picture of each Stage w/ labels - Chromosomes - Centromeres - Spindle Fibers & Nucleus (when applicable) A detailed description of exactly what is happening in each stage. Color is required