Mitosis and the Cell Cycle Big Idea Mitosis
Mitosis and the Cell Cycle Big Idea: Mitosis is the process in which the nucleus divides to form two new nuclei and two cells with identical DNA. 1 1
How do little elephants grow up to be BIG elephants?
Why do animals shed their skin?
Mitosis begins after fertilization 1 cell becomes 2 cells, becomes 4 cells…becomes TRILLIONS
Why do cells make more cells? Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement
Important Terms Somatic Cells – body cells › Produced through mitosis › Has 46 chromosomes (23 pairs) Homolog – each member of a chromosome pair Diploid (2 n) – total of 46 chromosomes in people – zygote & somatic cells Haploid (n) – total of 23 chromosomes in people, gametes (sperm & egg)
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 • Nucleus CELL MEMBRANE Cytoplasm
Interphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
Stages of Interphase Growth Stage 1 (G 1) – metabolic activity of the cell Synthesis Stage (S) – metabolic activity of the cell, replication of DNA Growth Stage 2 (G 2) – metabolic activity of the cell, prepare for division
Prophase 1 st step in Mitosis begins (cell begins to divide). • Centrioles (or poles) appear and begin to move to opposite ends of the cell. • Nuclear Envelope disappears. • Spindle fibers form between the poles. • Sister chromatids Centrioles Spindle fibers
Prophase Animal Cell Plant Cell Spindle fibers Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
Metaphase 2 nd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers at the centromere. • Chromosomes move to the equator of the cell. • Centrioles Spindle fibers
Metaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
Anaphase 3 rd step in Mitosis Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. • Centromere is broken in half. • Centrioles Spindle fibers
Anaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
Telophase 4 th step in Mitosis Two new identical nuclei form (nuclear envelopes reform). • Chromosomes uncoil and appear as chromatin (threads rather than rods). • Mitosis ends. • Nuclei Chromatin Nuclei
Telophase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/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 Interphase
Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase
REMEMBER! Interphase Prophase Metaphase Anaphase Telophase Cytokinesis IPMATC I Prefer Meatloaf At Tennis Camp
Cell Cycle 23
- Cell Division The Cell Cycle 24 24
Mitosis Animation http: //www. cellsalive. com/mitosis. htm
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