Cell Cycle 3 Steps Interphase cell growth and development Longest phase Mitosis cell reproduction creating 2 new nuclei Cytokinesis cell reproduction finishes creating 2 new cells (DAUGHTER)

Importance of Cell Division Some cells get old and wear out New cells formed by the cell cycle replace old cells before they die For example: every human is shedding old skin cells. We loose about 40,000 cells every minute. Cells lining the stomach are replaced every week because your stomach is so acidic New cells formed by the cell cycle replace old cells before the cell dies.

Vocabulary Preview Cell Cycle Interphase Mitosis Cytokinesis Prophase Metaphase Anaphase Telephase Cytokinesis Homologous Chromosome Daughter Cell Sister Chromatid Centromere Cell Plate

Length of a Cell Cycle The length of a cell cycle is different for each type of organism and every different type of cell (skin, heart, lung, etc…) When organisms are young and growing, the cell cycle repeats more quickly. An example: A zebra fish grows from 1 cell to 256 cells in 15 minutes http://www.teachersdomain.org/asset/lsps07_int_devdance/

Preview Cell Division http://iknow.net/player_window.html?url=media/cell_cycle_intro_auto.swf&width=360&height=285 Enlarge Screen for a bigger view

Phases of the Cell Cycle

RESULTS OF CELL DIVISION After Mitosis and Cell Division, the original cell, called the parent cell NO LONGER EXISTS After the cell cycle (at the end of cytokinesis) 2 new identical cells (called Daughter cells) are created. They are genetically identical to the parent cell. Think Write Pair Share: What happened to the original parent cell? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Interphase First Phase of the Cell Cycle Chromosomes (which is another name for the DNA) in the nucleus are like a bunch of spaghetti noodles. For each chromosome there is an identical chromosome. This identical pair is called homologous chromosomes. Humans have 23 pairs of homologous chromosomes.

Phase in Interphase Interphase has three phases G1, S, and G2. G1 Cells grow perform cell functions (do their job) S DNA is copied G2 perform cell functions (do their job), all organelles are copied

Mitosis 2nd part of the Cell Cycle Mitosis is a continuous process. PMAT It is made up of 4 phases Prophase Metaphase Anaphase Telophase PREVIEW: http://highered.mcgraw-hill.com/sites/0073031216/student_view0/exercise13/mitosis_movie.html

Prophase The first phase of mitosis is Prophase. 1) Chromosomes (DNA) twist (condense) into tight coils 2) Nucleus breaks apart

Metaphase During Metaphase, all the chromosomes that are attached to the fibers move to the middle of the cell. The pairs line up end to end, across the center of the cell. “Meet in the middle”

Anaphase During Anaphase, The chromosomes are pulled apart making 2 sister chromatids. The sister chromatids are pulled to opposite sides of the cell http://www.copernicusproject.ucr.edu/ssi/HSBiologyResources.htm

Telophase During Telophase, a new nuclear membrane forms around the separated chromatids making 2 identical nuclei in 1 cell.

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

Cytokinesis

Cytokinesis

Viewing Cell Division Cell Cycle, Animal Mitosis, & Plant Mitosis Mitosis: http://www.iknow.net/player_window.html?url=media/prophase_video_auto.swf&width=360&height=285 Plant Cell Mitosis: http://www.iknow.net/player_window.html?url=media/plant_mitosis_auto.swf&width=360&height=285 Microscopic: http://www.teachersdomain.org/asset/tdc02_vid_dnadivide/ Hand Drawn: http://www.layyous.com/Videoclips/mitosis.htm Living Cell-Time lapse photography: http://www.phschool.com/science/biology_place/labbench/lab3/mitfilm.html

Writing to Learn ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________