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Mitosis

Mitosis. Definition. Mitosis = is the process of the nuclear division in eukaryotes that produces two individual daughter cells. . Mitosis in single-celled organisms: responsible for the production of new individuals- asexual reproduction. Examples: Paramecia and Amoeba .

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Mitosis

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  1. Mitosis

  2. Definition • Mitosis = is the process of the nuclear division in eukaryotes that produces two individual daughter cells.

  3. Mitosis in single-celled organisms: responsible for the production of new individuals- asexual reproduction. • Examples: Paramecia and Amoeba • Mitosis in multi-cellular organisms: responsible for growth of the organism and repair of damaged tissues. • Example: Plants and Animals

  4. DNA: (deoxyribonucleic acid) genetic material of the cell. • First, it must be replicated so that there is a duplicate set of genetic information that can be given to each daughter cell. • Second, the genetic material (DNA) must be divided so that each daughter cell gets exact same set of information

  5. In humans and plants it is in the form of chromosomes, which are structures made up of DNA and associated proteins to maintain the shape of the DNA. These proteins are involved in packaging the DNA tightly so it will fit in the cell. • 46 chromosomes arranged in 23 pairs (1 set form mom and 1 set form dad). Each pair is a homologous pair of chromosomes. (Same size, shape and contain the same type of genetic information, or genes)

  6. A cell normally has two sets (like us) is diploid, while the cell that has one set (a sperm or an unfertilized egg) is haploid. • MUST be replicated and divided so that the genetic information can be transferred to each new cell.

  7. Three Steps of Mitosis: • Replication of genetic material from the mother cell. • Separation of the replicated genetic material. • Formation of the two daughter cells.

  8. Interphase Chromosome • Chromosomes are extended (not condensed) and therefore not visible. • Chromosome replicate * Each chromosome is now made up of two identical sister chromatids joined at a centromere. *There is now twice the genetic information, although the same number of chromosomes as before

  9. Centriole replicate • Nuclear membrane (envelope) is still present. • Nucleolus is visible.

  10. Prophase • Chromosomes condense • Nucleolus disappears • Nuclear membrane disappears • Spindle apparatus, composed of spindle fibers, forms and centrioles migrate apart. • Each chromosome becomes attached to a spindle fiber.

  11. Metaphase • Chromosome align in the middle (equator) of the cell; are pulled by the spindle fibers.

  12. Anaphase • Centromere of each chromosome splits and one chromatid from each chromosome moves to centrioles at the poles of the cell. • The chromatids, which are now separate, are called chromosomes. • There are now twice as many chromosomes in the cell as there were in the parent cell.

  13. Telophase • Nuclear membranes reform around each group of newly divided chromosomes. • Nucleolus reappears • Spindles disappear • Chromosomes extend, becoming invisible

  14. Cytokinesis occurs (cytoplasmic division of all the other materials in the cell such as the cytoplasm, cell membrane, and organelles) that result in the formation of two daughter cells with the correct number of chromosomes.

  15. Animals: The cell membrane pinches inward from both sides between the two poles until two daughter cells are formed • Plants: Plant cells form a region of new membranes and new cell wall material in the middle of the cell, which moves outward. This is called a cell plate.

  16. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  17. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  18. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  19. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  20. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  21. Figure 10–5 Mitosis and Cytokinesis Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

  22. M phase (Mitosis) Interphase G1 phase S phase G2 phase Prophase Metaphase Anaphase Telophase Concept Map Section 10-2 Cell Cycle includes is divided into is divided into Go to Section:

  23. NOTE: • Uncontrolled mitosis= CANCER!!!

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