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Cell Division

Learn about mitosis, the process by which cells reproduce themselves through a series of stages, resulting in daughter cells with the same genetic material as the parent cell. Explore the phases of mitosis, the cell cycle, and the importance of cell division in our bodies.

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Cell Division

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  1. Cell Division Mitosis: the process by which cells reproduce themselves, resulting in daughter cells that contain the same amount of genetic material as the parent cell. Simply put…how one cell becomes two

  2. Cell Division Occurs in a series of stages of phases • Cell Division refers to the ENTIRE process • Mitosis is a phase of the cell cycle • Mitosis, itself, has four phases (Prophase, Metaphase, Anaphase, Telophase)

  3. Animated Mitosis Cycle http://www.cellsalive.com/mitosis.htm • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis

  4. Life cycles of different cells: Our bodies are made up of tiny cells.They can only be seen with a microscope. Like people, cells grow and die. We make new cells through MITOSIS

  5. DID YOU KNOW??? • OUR BODIES MAKE 1,000,000,000 (ONE BILLION) CELLS EVERY DAY???? • OUR CELLS ARE CONSTANTLY DIVIDING. • MITOSIS IS HOW WE MAKE NEW CELLS, AND GET RID OF OLD, DEAD CELLS.

  6. New Body Cells The Cell Cycle (aka Cell Division and Mitosis) is how we make new body cells. Our body cells are called “somatic” (SO-mat-TICK) All cells in our body (somatic cells) reproduce through MITOSIS, except our GAMETES (or sex cells)—meaning sperm or eggs. Sperm and eggs reproduce through MEIOSIS

  7. interphase • Has 3 phases • G1 (growth) • S (DNA synthesis, DNA replication) • G2 (growth) • A cell spends 75% (3/4) of its life in Interphase

  8. Interphaseoccurs 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 CELL MEMBRANE Nucleus Cytoplasm

  9. Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  10. Prophase 1st step in Mitosis • Mitosis begins (cell PREPARES to divide) • Centrioles(or poles) appear and begin to move to opposite end of the cell. • Sister Chromatidsbecome visible. Centrioles Sister chromatids Spindle fibers

  11. Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  12. Metaphase 2nd step in Mitosis • Chromatids (or pairs of chromosomes) attach to the spindle fibers in the MIDDLE of the cell. Centrioles Spindle fibers

  13. Metaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  14. Anaphase 3rdstep in Mitosis • Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Chromatids pull APART Centrioles Spindle fibers

  15. Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  16. Telophase4th step in Mitosis • Two new nuclei form. • Chromosomes appear as chromatin (threads rather than rods). • Mitosis ends. Nuclei Nuclei Chromatin

  17. Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

  18. Cytokinesisoccurs after mitosis • Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

  19. Animal Mitosis -- Review

  20. Plant Mitosis -- Review

  21. Cell Cycle

  22. - Cell Division The Cell Cycle 23

  23. Count the number of cells in each stage

  24. Cancer and Mitosis It’s important that cells have a cycle of growth and death. Some cells fail to die and continually divide (Mitosis) Cells that continually divide and continue to build up. This is called a tumor A malignant tumors is cancerous. A benign tumor is non-cancerous.

  25. Cancer & Mitosis If cells do not die, cancer is likely to develop (as the result tumors) So, if cells continue to divide (undergo Mitosis), tumors and cancer will develop. Apoptosis (programmed cell death) is necessary. A person’s health could be a stake if there is an error in Mitosis and cells fail to die.

  26. Examples of tumors These images are examples of tumors. Cancer can take place on any part of the body. The entire body is made of cells, and cancer starts with cells Raise Cancer Awareness!

  27. Cancer & Causes Genetics (heredity): some cancers are passed along family lines (breast cancer, prostate cancer) Diet and obesity: colon cancer is caused by those who consume a diet high in fat Environmental factors: 2nd hand smoking-those who do not smoke can also get cancer because of those who smoke around them Sun/UV rays: extended exposure to UV rays can cause skin cancer (melanoma)

  28. MitosisAnimation http://www.cellsalive.com/mitosis.htm Watch the animation! See how one cell divides into two!

  29. The facts.. • Males make sperm; females make eggs • Males go through meiosis until they are in their 70s (men make sperm until they are elderly) • Ladies are born with the number of eggs they will have until menopause

  30. MEIOSIS vs. MITOSIS • Meiosis is how the body makes more gametes (sex cells). • Meiosis is NOT sexual reproduction. • Simply put, Meiosis is how we make sperm or eggs

  31. Mitosis vs. Meiosis

  32. Diploid vs. Haploid (chromosome number) • Mitosis – diploid (2n) • Cells that divide and reproduce by MITOSIS are diploid. • They have the same # of chromosomes as the parent cell • Ex. If my liver cell has 46 chromosomes, the daughter cells will have 46 • Meiosis – Haploid (n) Cells that divide and reproduce by MEIOSIS are HAPLOID. • They have half the number of chromosomes as the parent cell. • Ex. If an egg cell with 46 chromosomes goes through meiosis, the daughter cells will have 23 chromosomes

  33. Examples of Diploid & Haploid • Cells that are diploid reproduce by Mitosis. • Example: a Liver cell that is reproducing through mitosis has 46 chromosomes. After Mitosis, the new daughter cells have 46 chromosomes. • Cells that are haploid reproduce by Meiosis. • Example: A man’s sperm has 46 chromosomes. After it goes through Meiosis, the daughter cells have 23 • Gametes (sex cells) are HAPLOID (half)

  34. Reinforcement • Somatic = body cell • Mitosis • Diploid (2n) • Gamete = sex cell • Meiosis • Haploid (n)

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