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Cell Division Chapter 10. Why do you think cells in all plants and organisms need to divide?  To replace damaged tissue  To increase in size (the organism)

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Presentation on theme: "Cell Division Chapter 10. Why do you think cells in all plants and organisms need to divide?  To replace damaged tissue  To increase in size (the organism)"— Presentation transcript:

1 Cell Division Chapter 10

2 Why do you think cells in all plants and organisms need to divide?  To replace damaged tissue  To increase in size (the organism)  To reproduce

3 Repair Cells are constantly repairing themselves If a cell can’t be repaired new ones are produced to fill the void

4 Growth Cells are also what create our size As we grow our cells are constantly reproducing If the reproduction rate is faster than normal, we grow

5 Reproduction Asexual Done by somatic or body cells Done also by unicellular organisms Creates identical daughter cells Sexual Done by gametes or sex cells Creates genetically different daughter cells

6 What does the DNA look like inside the nucleus of the cell? When the cell is not dividing, the DNA looks like a tangled mass called CHROMATIN

7 When the cell is ready to divide, the DNA condenses into CHROMOSOMES Chromosome: a compacted piece of chromatin that is used for cell division Sister Chromatids: A pair of identical Chromosomes Centromere: The center section where the sister chromatids are connected Sister chromatids Centromere TEM 36,600 

8 DNA supercoil

9 LE 8-4 Sister chromatids Centromere TEM 36,600  Sister chromatids Chromosome distribution to daughter cells Chromosome duplication

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11 How do cells divide? Cell Cycle: an orderly sequence of events where cells divide The cell cycle consists of two major phases – Interphase (90% of the time) – Mitotic Phase/cell division (10% of the time) hill.com/sites/ /student_view0/chapter2/animation__how_the_cell_c ycle_works.html

12 The Cell Cycle In humans and other mammals, cells that reproduce daily have a cell cycle that usually lasts 10 to 20 hours.

13 The Cell Cycle: series of events that cells go through from “birth” to reproduction

14 Interphase Phase where all metabolic processes and functions happen – Ex: Cellular respiration Protein creation Movement Growth Other desired function

15 Interphase Interphase is also when the cell prepares for cell division – Ex: Increases proteins Duplicates organelles Grows in size Replication (duplication) of DNA

16 Mitotic Phase The division phase of the cell There are two main parts of M phase – Mitosis – Cytokinesis

17 Mitotic phase Mitosis – The division of a cells nucleus and DNA into two equal parts – Creates two daughter nuclei Cytokinesis – The division of the cells cytoplasm Together they create two identical daughter cells

18 Mitosis Prophase: – Sister chromatids are formed – Formation of spindle – Nuclear envelope breaks down Metaphase: – Sister chromatids line up – Spindle is formed and attaching to chromosomes

19 LE 8-6a I NTERPHASE P ROPHASE P ROMETAPHASE Kinetochore Fragments of nuclear envelope Centrosome Early mitotic spindle Chromatin Centrosomes (with centriole pairs) LM 250  Nucleolus Nuclear envelope Plasma membrane Chromosome, consisting of two sister chromatids Centromere Spindle microtubules

20 Mitosis Anaphase: – Separation of sister chromatids – Spindle pulls chromosomes to either side of the cell Telophase: – Spindle breaks down – Nuclear envelopes form (2) – Chromosomes loosen to become chromatin Cytokinesis: – After mitosis, cell pulls apart to create two identical cells

21 LE 8-6b M ETAPHASE A NAPHASETELOPHASE AND C YTOKINESIS Metaphase plate Spindle Daughter chromosomes Nuclear envelope forming Cleavage furrow Nucleolus forming

22 Cytokinesis in animal cells Animal Formation begins with indentation Cell is pulled/ pinched until it breaks apart Plants Formation begins with a disc containing cell wall materials A cell plate forms between the two nuclei Cleavage furrow Cleavage furrow Daughter cells Cleavage furrow Contracting ring of microfilaments SEM 140 

23 Cytokinesis in plant cells Formation begins with a disc containing cell wall materials A cell plate forms between the two nuclei Cell wallNew cell wall Daughter cellsCell plateVesicles containing cell wall material

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25 Benign vs. malignant tumor Benign tumor: – abnormal mass of normal cells Malignant tumor: Masses of cells that result from the reproduction of cancer cells Cancer – Disease caused by cells that loose their ability to control rate of division

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28 Cell Differentiation


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