Copyright Pearson Prentice Hall 10-2 Cell Division Photo Credit: © CAMR/A.B. Dowsett/Science Photo Library/Photo Researchers, Inc. Copyright Pearson Prentice Hall

Chromosomes hold genetic information. Before cell division, each chromosome is copied.

Copyright Pearson Prentice Hall Chromosomes “Sister” chromatids: 2 identical chromatids. Centromere: Each pair of chromatids attached at an area. Sister chromatids Photo Credit: © Gunther F. Bahr/AFIP/Stone Centromere Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Cell Cycle During the cell cycle: a cell grows prepares for division divides to form two daughter cells, each of which begins the cycle again Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Cell Cycle Cell cycle consists of four phases: G1 S Phase G2 M Phase Copyright Pearson Prentice Hall

Events of the Cell Cycle During G1, the cell increases in size synthesizes new proteins and organelles Copyright Pearson Prentice Hall

Events of the Cell Cycle During the S phase, chromosomes are replicated DNA synthesis takes place Once a cell enters the S phase, it usually completes the rest of the cell cycle. Copyright Pearson Prentice Hall

Events of the Cell Cycle The G2 Phase: organelles and molecules required for cell division are produced Once G2 is complete, the cell is ready to start the M phase—Mitosis Copyright Pearson Prentice Hall

Events of the Cell Cycle M Phase During the cell cycle, the cell grows, replicates its DNA, and divides into two daughter cells. DNA synthesis takes place during the S phase. Cell division takes place during the M phase. G1 and G2 are gap phases. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis Four phases of Mitosis: Prophase Metaphase Anaphase Telophase Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis Spindle forming Prophase is the first and longest phase of mitosis. Centrioles separate and take up positions on opposite sides of the nucleus. Centromere Chromosomes (paired chromatids) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis:Prophase Spindle forming Centrosome: Region containing centromere and organizes spindle. Spindle: a fanlike microtubule structure that helps separate the chromosomes. Centromere Chromosomes (paired chromatids) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis: Prophase Spindle forming Chromatin condenses into chromosomes. The centrioles separate and a spindle begins to form. The nuclear envelope breaks down. Centromere Chromosomes (paired chromatids) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis Centriole Metaphase The chromosomes line up across the center of the cell. Microtubules connect the centromere of each chromosome to the poles of the spindle. Spindle Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis Anaphase The sister chromatids separate into individual chromosomes. The chromosomes continue to move until they have separated into two groups. Individual chromosomes Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis Telophase Chromosomes gather at opposite ends of the cell and lose their distinct shape. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mitosis: Telophase A new nuclear envelope forms around each cluster of chromosomes. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Cytokinesis During cytokinesis, the cytoplasm pinches in half. Each daughter cell has an identical set of duplicate chromosomes Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Cytokinesis in Plants In plants, a structure known as the cell plate forms midway between the divided nuclei. Cell plate Cell wall Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 - or - (must have QuickTake software installed on the computer you are using for this presentation) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 The series of events that cells go through as they grow and divide is called the cell cycle. mitosis. interphase. cytokinesis. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 The phase of mitosis during which the chromosomes line up across the center of the cell is prophase. metaphase. anaphase. telophase. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 Cytokinesis usually occurs at the same time as telophase. after telophase. during interphase. during anaphase Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 DNA replication takes place during the S phase of the cell cycle. G1 phase of the cell cycle. G2 phase of the cell cycle. M phase of the cell cycle. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 10-2 During mitosis, “sister” chromatids separate from one another during telophase. interphase. anaphase. metaphase. Copyright Pearson Prentice Hall

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