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Page 1 Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi Lesson: Cell Cycle - Mitosis and Meiosis Lesson Developer: Rama Sisodia College/ Department: Department of Botany, Maitreyi College, University of Delhi Page 2 Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi Lesson: Cell Cycle - Mitosis and Meiosis Lesson Developer: Rama Sisodia College/ Department: Department of Botany, Maitreyi College, University of Delhi Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 1 Table of Contents Chapter: Cell Cycle ? Introduction ? Phases of cell cycle ? Interphase ? Mitosis ? Prophase ? Metaphase ? Anaphase ? Telophase ? Cytokinesis ? Meiosis ? Stages of meiosis ? Meiosis I ? Meiosis II ? Cytokinesis ? Significance of meiosis ? Meiosis in animals: Oogenesis and Spermatogenesis ? Summary ? Exercise/ Practice ? Glossary ? References/ Bibliography/ Further Reading Page 3 Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi Lesson: Cell Cycle - Mitosis and Meiosis Lesson Developer: Rama Sisodia College/ Department: Department of Botany, Maitreyi College, University of Delhi Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 1 Table of Contents Chapter: Cell Cycle ? Introduction ? Phases of cell cycle ? Interphase ? Mitosis ? Prophase ? Metaphase ? Anaphase ? Telophase ? Cytokinesis ? Meiosis ? Stages of meiosis ? Meiosis I ? Meiosis II ? Cytokinesis ? Significance of meiosis ? Meiosis in animals: Oogenesis and Spermatogenesis ? Summary ? Exercise/ Practice ? Glossary ? References/ Bibliography/ Further Reading Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 2 Introduction One of the characteristic features of living organisms is their capacity to grow and reproduce. As the cells grow in size, the limited capacity to expand as the cells increase in size to accommodate the increasing contents necessitates the cell to divide. Cells arise by division of existing cells (“Omnis cellula e cellula”, Rudlof Virchow, 1955). Cell division plays an important role in - ? single celled prokaryotes, for e.g. amoeba that divided asexually by a simple process of binary fission. Figure: Amoeba proteus dividing by binary fission. The division of the nuclei is followed by the separation of the cytoplasm to form two daughter cells. Source: http://biodiversitywiki- shayna.wikispaces.com/file/view/amoeba8.jpg/175484073/amoeba8.jpg (cc) ? growth and development of multicelled eukaryotic organisms. The multicelled organisms begin their life from a single celled zygote that divides and differentiates to assume the form and function of an adult. Page 4 Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi Lesson: Cell Cycle - Mitosis and Meiosis Lesson Developer: Rama Sisodia College/ Department: Department of Botany, Maitreyi College, University of Delhi Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 1 Table of Contents Chapter: Cell Cycle ? Introduction ? Phases of cell cycle ? Interphase ? Mitosis ? Prophase ? Metaphase ? Anaphase ? Telophase ? Cytokinesis ? Meiosis ? Stages of meiosis ? Meiosis I ? Meiosis II ? Cytokinesis ? Significance of meiosis ? Meiosis in animals: Oogenesis and Spermatogenesis ? Summary ? Exercise/ Practice ? Glossary ? References/ Bibliography/ Further Reading Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 2 Introduction One of the characteristic features of living organisms is their capacity to grow and reproduce. As the cells grow in size, the limited capacity to expand as the cells increase in size to accommodate the increasing contents necessitates the cell to divide. Cells arise by division of existing cells (“Omnis cellula e cellula”, Rudlof Virchow, 1955). Cell division plays an important role in - ? single celled prokaryotes, for e.g. amoeba that divided asexually by a simple process of binary fission. Figure: Amoeba proteus dividing by binary fission. The division of the nuclei is followed by the separation of the cytoplasm to form two daughter cells. Source: http://biodiversitywiki- shayna.wikispaces.com/file/view/amoeba8.jpg/175484073/amoeba8.jpg (cc) ? growth and development of multicelled eukaryotic organisms. The multicelled organisms begin their life from a single celled zygote that divides and differentiates to assume the form and function of an adult. Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 3 Figure: The single celled zygote divides by repeated divisions and eventually develops into an individual. Source: http://upload.wikimedia.org/wikipedia/commons/c/c4/Gray9.png ? the continuous growth and renewal of cells in multicelled eukaryotes. There are two types of cell division: 1. Mitosis – is a type of cell division involved in the development of a single celled zygote into an adult organism, growth and repair of tissues and in asexual reproduction. In mitosis the parent cell divides into two daughter cells that are genetically identical to parent cell,i.e. the chromosome number is same to parent cell. The fidelity of the process ensures the heritable transmission of traits essential for maintaining the continuity of life. 2. Meiosis - by which the germ cells divide to form gametes. Each parent cell produces four daughter cells in which the chromosome number is reduced to half. Meiosis involves genetic recombination by the process of crossing over. Phases of cell cycle Page 5 Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi Lesson: Cell Cycle - Mitosis and Meiosis Lesson Developer: Rama Sisodia College/ Department: Department of Botany, Maitreyi College, University of Delhi Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 1 Table of Contents Chapter: Cell Cycle ? Introduction ? Phases of cell cycle ? Interphase ? Mitosis ? Prophase ? Metaphase ? Anaphase ? Telophase ? Cytokinesis ? Meiosis ? Stages of meiosis ? Meiosis I ? Meiosis II ? Cytokinesis ? Significance of meiosis ? Meiosis in animals: Oogenesis and Spermatogenesis ? Summary ? Exercise/ Practice ? Glossary ? References/ Bibliography/ Further Reading Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 2 Introduction One of the characteristic features of living organisms is their capacity to grow and reproduce. As the cells grow in size, the limited capacity to expand as the cells increase in size to accommodate the increasing contents necessitates the cell to divide. Cells arise by division of existing cells (“Omnis cellula e cellula”, Rudlof Virchow, 1955). Cell division plays an important role in - ? single celled prokaryotes, for e.g. amoeba that divided asexually by a simple process of binary fission. Figure: Amoeba proteus dividing by binary fission. The division of the nuclei is followed by the separation of the cytoplasm to form two daughter cells. Source: http://biodiversitywiki- shayna.wikispaces.com/file/view/amoeba8.jpg/175484073/amoeba8.jpg (cc) ? growth and development of multicelled eukaryotic organisms. The multicelled organisms begin their life from a single celled zygote that divides and differentiates to assume the form and function of an adult. Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 3 Figure: The single celled zygote divides by repeated divisions and eventually develops into an individual. Source: http://upload.wikimedia.org/wikipedia/commons/c/c4/Gray9.png ? the continuous growth and renewal of cells in multicelled eukaryotes. There are two types of cell division: 1. Mitosis – is a type of cell division involved in the development of a single celled zygote into an adult organism, growth and repair of tissues and in asexual reproduction. In mitosis the parent cell divides into two daughter cells that are genetically identical to parent cell,i.e. the chromosome number is same to parent cell. The fidelity of the process ensures the heritable transmission of traits essential for maintaining the continuity of life. 2. Meiosis - by which the germ cells divide to form gametes. Each parent cell produces four daughter cells in which the chromosome number is reduced to half. Meiosis involves genetic recombination by the process of crossing over. Phases of cell cycle Cell Cycle - Mitosis and Meiosis Institute of Lifelong Learning, University of Delhi 4 Embed Animation: https://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_cell_cycle_works. html The life of a cell from the time it is formed to its division is called as cell cycle. The cell cycle consists of several well-coordinated phases – growth of the cell, replication of DNA, distribution of replicated chromosomes between the two daughter cells and cell division. The entire cell cycle in a eukaryotic cell as shown by a cultured human cell takes 24 hrs to complete. This is divided in a long interphase (23 hrs) which is further divisible into three phases- G1, S and G2, and short divisional stage- mitosis (1 hr). Figure: The cell cycle Source: http://www.hartnell.edu/tutorials/biology/images/cellcyclediagram.jpg (CC-BY-SA) The duration of the four phases of cell cycle differs in various cell types. In a human cell which is rapidly proliferating the total 24 hr cycle has a 11 hr G 1 phase, 8 hrs S phase, G 2 of about 4 hrs and M phase of 1 hr. The cell cycle is considerably shorter in rapidly dividing cells like Saccharomyces cerevisiae (90 min) and early embryo cells (30 min). The latter has no gap phase and has a very short S phase.Read More
1. What is the cell cycle? |
2. What is mitosis? |
3. What is meiosis? |
4. What is the difference between mitosis and meiosis? |
5. What are the key events that occur during the cell cycle? |
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