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Cell Growth and Division

CHAPTER 5. Cell Growth and Division. Why do cells reproduce?. To help organisms:. GROW. ________________________. We grow because our cells divide. REPAIR. ________________________. Fingernail growth slows due to mitosis slowing down. Stomach lining cells: 2 days.

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Cell Growth and Division

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  1. CHAPTER 5 Cell Growth and Division

  2. Why do cells reproduce? To help organisms: GROW ________________________ We grow because our cells divide REPAIR ________________________ Fingernail growth slows due to mitosis slowing down.

  3. Stomach lining cells: 2 days ______________________ Life Spans of Body Cells Ex: Skin cells Lung cells Platelets: 10 days ______________________ Skin Cells: 20 days ______________________ Red Blood Cells: 120 days ______________________ Brain cells: 30-50 years ______________________ Intestinal lining cells: 3 days ______________________

  4. chromatid telomere centromere telomere Condensed, duplicated chromosome Condensed, duplicated chromosome Chromosomes • DNA plus proteins is called chromatin. • Strand of protein that attaches to The chromosome is called a fiber. • One half of a duplicated chromosome is a chromatid. • Sister chromatids – chromosome after it has made an exact copy. Held together at the centromere. • Telomeres protect DNA and do not include genes. • Before the first step of Mitosis chromosomes make exact copies of themselves.

  5. The Cell Cycle • The four stages of the cell cycle are gap 1, synthesis, gap 2, and mitosis. 1) Gap 1 (G1): cell growth and normal functions 2) DNA synthesis (S): copies DNA 3) Gap 2 (G2): additional growth 4) Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis) • Mitosis occurs only if the cell is large enough and the DNA undamaged.

  6. Mitosis Parent cell centrioles spindle fibers centrosome nucleus with DNA Mitosis and cytokinesis produce two genetically identical daughter cells. • Mitosis- the process of making new body cells • Interphase prepares the cell to divide. Inter=G1-S-G2 • During interphase, the DNA is duplicated.

  7. Steps of Mitosis • Prophase • Metaphase • Anaphase • Telophase _______________________________________ _______________________________________ _______________________________________ _______________________________________ PMAT

  8. PROPHASE Shorten and Thicken Begins to break down Move apart from one another Form between centrioles

  9. METAPHASE Become attached to the fibers. Are pulled to middle of cell Are stretched between the two ends of cell Move to opposite ends of cells Remains dissolved

  10. ANAPHASE Pulled apart by fibers. Each chromatid is separate from its “sister” Still at cell’s poles; Pull each chromatid toward opposite ends of cell Remains dissolved

  11. TELOPHASE Each end of cell has a complete set of chromosomes. Begins to pinch, forming two new cells Begin to disappear Begins to reform

  12. Mitosis • Cytokinesis differs in animal and plant cells. • In animal cells, the membrane pinches closed. • In plant cells, a cell plate forms.

  13. The Point of Mitosis Result in two IDENTICAL daughter cells Each cell will have the SAME number of chromosomes as the original cell. Each cell will have the SAME job as the original cell.

  14. MITOSIS Plant Cell vs. Animal Cell • The process is VERY SIMILAR in each type of cell. • There are only 2 differences: • Plant cells do not have centrioles • A cell wall is laid down at the end of the cell division.

  15. Plant cell Animal Cell Cell Wall Chloroplasts

  16. Animal Cell

  17. Plant cell

  18. Anaphase Prophase Metaphase Telophase

  19. Animal Cell Plant cell Centrioles are not always found in plant cells.

  20. Can You Put These Cells In The Correct Sequence Of Mitosis? ??So What Is This?? 3. Anaphase 2. Metaphase ___________________ ___________________ ___________________ ??So What Is This?? 1. Prophase 4. Telophase ___________________ ___________________ ___________________

  21. Mitosis is only a small part of a cell's "LIFE CYCLE" _____________________________ (Just like you; You will only spend a short time of your life actually reproducing!") At least...LET'S HOPE SO! INTERPHASE The cell spends most of its life in ____________________ (The phase IN-BETWEEN mitosis) Life Cycle Animation

  22. Can You Put These Cells In The Correct Sequence Of Mitosis? 3. Anaphase Interphase 2. Metaphase ___________________ ___________________ ___________________ 1. Prophase Interphase 4. Telophase ___________________ ___________________ ___________________ Mitosis video - DS

  23. Rates of Mitosis An organism's cells are in different parts of their life's cycle. Can you identify the phases of this plant's cells? __________ ______________ __________ ______________ ______________

  24. Changes in the Rate of Mitosis Changes often occur in the growth rate of cells. Faster Rate of Mitosis: CANCER _______________________ Slower Rate of Mitosis: AGING _______________________ Signs of Aging: Loss of Hair Loss of Calcium Wrinkles

  25. normal cell cancer cell bloodstream Cancer Cell division is uncontrolled in cancer. • Cancer cells form disorganized clumps called tumors. They cause problems by crowding normal cells. • Benign tumors remain clustered and can be removed. • Malignant tumors metastasize, or break away, and can form more tumors.

  26. Cancer • Cancer cells do not carry out necessary functions and crowd out normal cells. • Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.

  27. Cancer • Carcinogens are substances known to promote cancer. • Standard cancer treatments typically kill both cancerous and healthy cells.

  28. CANCER CAUSERS SOME VIRUSES RADIATION 1._________________________ 2._________________________ Sun X-Rays ______________ ______________ CHEMICALS 3._________________________ Chemicals used on household items and/or pesticides Nuclear Wastes Drugs __________________ __________________ ____________________

  29. CHROMOSOMES OF ORGANISMS 32 78 48 36 94 18 18 16 78 64 46 6 14 1-4 20 26

  30. Chromosome Comparisons If an organism has more chromosomes, does that mean it is smarter? NO If an organism has more chromosomes, does that mean it is larger? NO If an organism has more chromosomes, does that mean it is more complex or evolved? NO

  31. Stem Cells Stem cells are unique body cells. • Stem cells have the ability to • divide and renew themselves • remain undifferentiated in form • develop into a variety of specialized cell types Meaning: The cell could become a lung cell, or a skill cell;… it is NOT predetermined!

  32. Stem Cells • Stem cells are classified into three types. • totipotent, or growing into any other cell type • pluripotent, or growing into any cell type but a totipotent cell • multipotent, or growing into cells of a closely related cell family

  33. Stem Cells First, an egg is fertilized by a sperm cell in a petri dish. The egg divides, forming an inner cell mass. These cells are then removed and grown with nutrients. Scientists try to control how the cells specialize by adding or removing certain molecules. • Stem cells come from adults and embryos. • Adult stem cells can be hard to isolate and grow. • The use of adult stem cells may prevent transplant rejection. • The use of embryonicstem cells raisesethical issues • Embryonic stem cellsare pluripotent andcan be grown indefinitelyin culture.

  34. Stem Cells • The use of stem cells offers many currently realized and potential benefits. • Stem cells are used to treat leukemia and lymphoma. • Stem cells may cure disease or replace damaged organs. • Stem cells may revolutionize the drug development process. Stem cells Ethical issue

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