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Cell Reproduction (cell division)

Cell Reproduction (cell division). p96. What is cell division? . Cell division  is the process by which a parent  cell  divides into two or more daughter cells . Cell division  usually occurs as part of a larger  cell  cycle. Why do cells divide/reproduce? .

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Cell Reproduction (cell division)

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  1. Cell Reproduction(cell division)

  2. p96 What is cell division? • Cell division is the process by which a parent cell divides into two or more daughter cells. • Cell division usually occurs as part of a larger cell cycle

  3. Why do cells divide/reproduce? • For organism growth, repair, and replacement of dead cells AND asexual reproduction (GRRR) • To maintain a workable cell to surface area ratio.(too big, DNA/nucleus can’t manage all the material)

  4. What does cell division for growth & repair look like? • One cell with 2 sets of chromosomes makes 2 cells with the same # of chromosomes=2N or two sets

  5. What are two types of reproduction that use cell division? • Asexual reproduction production of genetically IDENTICAL (clones) offspring from one parent • Sexual production of genetically DIFFERENT offspring from two parents

  6. Unicellular Organisms divide 1 cell for Use Asexual reproduction production of genetically IDENTICAL (clones) offspring from one parent EX: • Binary fission- cells splits into two. Used by all bacteria • Spores- form a protective wall and remain inactive until conditions favorable • Budding- cell pinches off from parent to form new individual

  7. Multicellular organisms Use Asexual production of genetically IDENTICAL offspring/tissue from one parent • Vegetative Propagation- occurs in plants where part of the plant is allow to develop into a whole new plant. Ex. Onion plants grow from stem of onion • Regeneration- the re-growing of a part of an organism when it is cut off and removed from that organism. Ex. Starfish regrows missing arm

  8. Multicellular organisms Sexual production of genetically DIFFERENT offspring from two parents • Step 1: Meiosis/making sex cells=sperm and egginvolves reducing the DNA in half EX: 2N / 2= N • Step 2: Fertilization/joining the sex cells- involves combining two half sets of DNA to create one full set EX: N+N = 2N

  9. What does cell division for making sperm and egg look like? • One cell with 2 sets of chromosomes makes 4 cells with half the # of chromosomes=N or one set

  10. What does fertilization look like? • One sperm and one egg each with 1 set of chromosomes =N join to form a unique cell (zygote=fertilized egg)

  11. Ssexual reproduction involves Meiosis AND Fertilization/joining the sex cells-

  12. Critical Questions • Name 3 reasons that cells must divide • 1. Growth • 2. Repair damaged cells • 3. Replace dead cells • Which type of asexual reproduction would bacteria (a unicellular organism) use? • Binary Fission • After cells divide asexually, are they exact clones of each other? • YES

  13. p98 What makes up a cell? Cells contain a nucleus. The nucleus has chromosomes inside. Chromosomes are made up of DNA. DNA has instructions that all cells need

  14. What is the cell cycle? • Thecell cycle or cell-division cycle is the series of events that include • DNA replication AND • Mitosis: division of the DNA & organelles that produces two daughter cells. • Cytokinesisdivides cytoplasm • Cell division usually occurs as part of a larger cell cycle

  15. https://www.youtube.com/watch?v=rgLJrvoX_qo

  16. Label the parts of the Cell cycle: • G1: growth • S: DNA replication • G2: growth & prepare for mitosis • M: prophase, metaphase, anaphase, telophase

  17. 3 parts of the Cell Cycle • Interphase • Growth and synthesis • Mitosis • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis

  18. https://www.youtube.com/watch?v=3CfvmWMzF2A

  19. Interphase: involves Growth and synthesis: cell matures and prepares for reproduction. • Replication (DNA is copied) makes duplicate copies for 2 new cells • organelles & cytoplasm copied

  20. 2. Mitosisis the division of the cells nucleus • It has 4 phases

  21. https://www.youtube.com/watch?v=C6hn3sA0ip0

  22. What cell parts are involved in cell division? • Centrioles • Make the spindle fibers • Chromosome • Made of coiled chromatin/DNA • Sister chromatids • Two copies of a chromosome

  23. Label the cell parts involved in cell division: • Centriole • Spindle fiber • Centromere • Chromosome • Sister chromatids

  24. Prophase • Chromosomes appear • Centrioles move to opposite poles • Spindle fibers begin to appear

  25. Metaphase • Chromosomes line up across the equator OR middle • Spindle fibers attach at the centromere

  26. Anaphase • Spindle fibers pull apart the two chromosomes • Divided chromosomes move to the opposite poles

  27. Telophase • Two identical new nuclei are then formed • Cytokinesis then begins to occur

  28. NOW…Label the phases of MITOSIS: • prophase • metaphase • anaphase • telophase

  29. telophase metaphase Two new nuclei prophase Chromosomes line up in middle Can you identify each phase? How can you tell each apart? anaphase One nuclei, chromosomes visible Chromosomes move apart

  30. 3. Cytokinesis • Cytoplasm divides and two identical daughtercells are formed

  31. https://www.youtube.com/watch?v=AEt8V53oddA

  32. How does cytokinesis differ inanimal vs plant? Animal cell membrane pinches in and forms a cleavage furrow plant cell membrane and a cell plate forms into a new cell wall

  33. Essential Questions • Why must the DNA be copied during interphase? • So there will be a complete set of chromosomes in each new cell • How do plant and animal cell division differ? • Plants form a cell plate, animals form a cleavage furrow. Animals have centrioles, plants do not.

  34. https://www.youtube.com/watch?v=pOsAbTi9tHw

  35. Critical Thinking • Cancer is uncontrolled cell division. How is mitosis important to a doctor studying cancer? • If a doctor knew how to stop mitosis in the cancer cells, then they would be able to stop the cancer from spreading to other parts of the body. This would then allow the doctors to remove the cancerous cells and save the patient

  36. Mitosis in Onion root tip

  37. p105 • Creates variation=differences • Uses two parents • Creates 4 different cells • Makes gametes=sex cells • Makes 4 haploid=N cells • Creates clones=copies • Uses One parent/cell • Produces 2 identical daughter cells • Makes somatic=body cells • Makes 2 diploid=2N cells

  38. p105 Mitosis vs Meiosis • Creates clones=copies • Uses One parent/cell • Produces 2 identical daughter cells • Makes somatic=body cells • Makes 2 diploid=2N cells • For Asexual reproduction • Creates variation=differences • Uses two parents • Creates 4 different cells • Makes gametes=sex cells • Makes 4 haploid=N cells • For sexual reproduction

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