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Cell Cycle & Cell Division Cell Cycle http://www.nobel.se/medicine/laureates/2001/press.html Stages of the Cell Cycle • Interphase • Mitosis • Cytokinesis Animated Cycle http://www.cellsalive.com/cell_cycle.htm INTERPHASE Interphase • Stage before cell division starts • Each chromosome in the nucleus makes an exact copy of itself. Interphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm MITOSIS Mitosis • Process during which the material from the cell nucleus divides. • Results in the production of two identical daughter cells from a single parent cell. • Used during growth or repair of cells. Stages of Mitosis (PMAT) • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis Prophase Nucleus Prepares for Cell Division • Genetic material shortens and thickens • Chromosome copies held together at their centers in “X” formation by centromere Prophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Metaphase • Two copies of each chromosome line up in the center of the cell. • Spindle fibers attach to chromosomes at the centromere (where they are joined). Metaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Anaphase • Spindle fibers pull chromosome copies apart • One complete set is pulled to one side and the other complete set is pulled to the other side of the cell. Anaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Telophase & Cytokinesis • Cytoplasm pinches in at the center of the cell, dividing the original cell in half. • 2 nuclei form • Daughter cells are identical to parent cell. Telophase & Cytokinesis • Each daughter cell ends up with the same number of identical chromosomes and about half the organelles and cytoplasm. Telophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Mitosis Animation http://www.cellsalive.com/mitosis.htm Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase Cell Cycle 1. Interphase 2a. Mitosis: Prophase 3. Cytokinesis 2b. Mitosis: Metaphase 2c. Mitosis: Anaphase 2d. Mitosis: Telophase Cell Cycle 1. Interphase 2a. Mitosis: Prophase 3. Cytokinesis 2b. Mitosis: Metaphase 2c. Mitosis: Anaphase 2d. Mitosis: Telophase Cell Cycle 1. Interphase 2a. Mitosis: Prophase 3. Cytokinesis 2b. Mitosis: Metaphase 2c. Mitosis: Anaphase 2d. Mitosis: Telophase MEIOSIS Meiosis • Type of cell division that produces sex cells (egg or sperm), which have only half the chromosomes of the parent cell. • One parent cell produces four daughter cells. • DNA replicates once, but the nucleus divides twice. Meiosis I • First division of meiosis • Each chromosome copies itself, X, before this stage. First Division of Meiosis • Prophase 1 & Metaphase 1 – Each chromosome in a cell has a homologous, or similar, pair. – Pairs line up two-by two in the center of the cell. • Anaphase 1: Each pair of homologous chromosomes separates from the other as they move to opposite sides of the cell. • Telophase 1: Cytoplasm splits and two new cells form. Each daughter cell contains only one homologous chromosome of the chromosome pair. (Half of the original genetic material of the original cell). Prophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Prophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Metaphase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Telophase I http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Meiosis II Second Division of Meiosis Second Division of Meiosis • Prophase 2: DNA does not replicate. • Metaphase 2: Chromosomes again line up in the center of the cell, but this time single-file instead of in pairs. • Anaphase 2: X-shaped chromosomes split and the copies separate. One copy goes to one side of the cell and the other is pulled to the other side. • Telophase 2: Cell division is complete with 4 new cells that have half the number of chromosomes that the original cell had. Four haploid (one set of chromosomes) daughter cells are formed. Prophase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Metaphase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Telophase II http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html Meiosis http://www.biosci.uga.edu/almanac/bio_103/notes/apr_3.html. Meiosis Animation http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/movie/meiosis.htm Mitosis vs. Meiosis • Mitosis – Growth or repair of cells – Cell divides once – Two (diploid) daughter cells – Genetic information is identical • Meiosis – Produces sex cells – Cell divides twice – Four (haploid daughter) cells – Half the genetic information is present Comparison Animations http://www.pbs.org/wgbh/nova/baby/divi_flash.html http://www.usoe.k12.ut.us/curr/science/sciber00/7th/gen etics/sciber/animatin.htm