Download to read offline
![Cell division-mitosis-meiosis-1225581257073362-9[1]](https://cdn.slidesharecdn.com/ss_thumbnails/cell-division-mitosis-meiosis-1225581257073362-91-111003031744-phpapp02-thumbnail.jpg?width=640&height=640&fit=bounds)
Cell division.pptx
- 1. Cell Division Mitosis &Meiosis
- 2. Cell Division What isit? Why do Cells do it? Why is it important to me?
- 3. Cell Division Also knownas Mitosis Takes place in Regular Body Cells Keeps Cells Living and Growing
- 4.
- 5. Mitosis The Basic Phases ofa Cell’s Life: •Interphase •Prophase •Metaphase •Anaphase •Telophase •Cytokinesis
- 6. Interphase The longest stage ofa Cell’s life The time spent between divisions Produces all materials required for growth Preparation for division
- 7. Part of Interphase is alsoknown as the G1 Phase of the Cell Cycle (Growth Phase)
- 8. The Second part of Interphaseis known as the S Phase of the Cell Cycle (Synthesis Phase – when DNA duplicates)
- 9. The third part ofthe Cell Cycle, G2, is just a checkpoint to make sure the DNA is correct. Next step – Mitosis
- 10. Mitosis: Cell Division The lastpart of the Cell Cycle is called Mitosis and has 4 phases during which the cell divides into 2 cells
- 11. Prophase The Cell begins thedivision process 1.The nucleolus disappears, 2.The nuclear membrane breaks apart
- 12. 3. The chromosomes becomevisible 4. The spindle apparatus forms and attaches to the centromeres of the chromosomes
- 13. Metaphase The Second Phase ofMitosis 4.The Nuclear Membrane is completely gone 2. The duplicated chromosomes line up along the cell's equator.
- 15. Anaphase The third phaseof Mitosis Diploid sets of daughter chromosomes separate They are pushed and pulled toward opposite poles of the cell by the spindle fibers
- 16.
- 17. Telophase The nuclear membrane and nucleoli(nucleus) reform. Cytokinesis is nearly complete,
- 18. The Cell Plate beginsto form The Cell prepares for finial division
- 19. Cytokinesis – Thefinal stage of Mitosis The cytoplasm, organelles, and nuclear material are evenly split and two new cells are formed. Cell Plate
- 20. The two newcells – each exactly like the other – are called Daughter Cells
- 21. Interphase – TheCell spends the majority of its life here, growing and functioning. During the S Phase of the Cell Cycle, the DNA replicates, in anticipation of Mitosis
- 22. In Early Prophaseof Mitosis the Chromosomes get small, centrioles move to the poles of the nucleus, and spindle fibers develop Pair of Centrioles Spindle Fibers Chromosomes consisting of 2 Sister Chromatids
- 23. Late Prophase happenswhen the Nuclear Envelope disintegrates and spindle fibers begin to move Chromosomes toward the center of cell. Spindle Fibers Chromosomes
- 24. During Metaphase theChromosomes line up across center of the cell, also called the equator, or Metaphase plate. Spindle Fibers Chromosomes Equator, or Metaphase Plate
- 25. In Anaphase theChromatids that make up each Chromosome move apart and travel to opposite ends of cellular spindle Daughter Chromosomes Chromosome Chromatid
- 26. In Telophase anenvelope surrounds each set of Chromatids to form new Nucleus and the Cytoplasm starts to divide Cleavage Furrow
- 27. Cytokinesis takes placewhen the Cytoplasm divides and two cells with identical genetic material are formed Daughter Cells
- 28. A B C DE Quick Review – Place Cells in Mitosis Order
- 29. Quick Review: Identify What happensin each phase of Mitosis: Prophase Metaphase Anaphase Telophase Interphase
- 30. Why Do CellsDivide? The larger a cell becomes, the more demands the cell places on it's DNA. It also has more trouble moving enough food and wastes across its cell membrane.
- 31. The bigger the cellgets the harder it becomes to move food and waste across the membrane Food goes in Waste goes out
- 32. This happens because the surface area and volume ratiodoes not stay the same as the cell size increases. Protein Pumps
- 33. The cell's ability toeither get substances from the outside or eliminate waste from the inside is related to the surface area of the cell membrane. (outside)
- 34. How much food andother material is required, and how much waste the cell produces and has to get rid of, is related to the volume of the cell. (inside)
- 35. As a cellgets bigger there comes a time when its surface area is not large enough to meet the demands of the cell's volume and the cell stops growing.
- 36. So, once cells reacha certain size they must divide in order to continue to function – or they will no longer be able to take in nutrients and eliminate waste.
- 37. Why Is CellDivision Important? 1. All Living Things are made of Cells
- 38. 2. The Cellis the basic unit of Structure and Function in Living Things.
- 39. 3. All Cellscome from pre existing Cells
- 40. You are aliving organism, made of cells. In order to keep living, your cells must stay alive. In order for cells to keep living, they must divide and multiply
- 41. Meiosis Why We AreWho We Are
- 42. Meiosis Takes place inthe Gametes of an organism People have a Chromosome count of 46 When an egg joins a sperm the count must stay at 46 to remain human So, the egg can only have 23 chromosomes, and the sperm can only have 23 chromosomes But, the integrity of the organism must be maintained. How does this happen?
- 43. During Meiosis gamete(sex) cells undergo a “double division”, maintaining the DNA, but reducing the chromosomal count to 23 + = Sperm (23) + Egg (23) = Fertilized Cell (46)
- 44. Chromosome after S Phase Chromosomesat beginning of Mitosis After Mitosis After Meiosis
- 45. Original Gamete MetaphaseAnaphase Telophase Cytokinesis 2 Daughter Cells Metaphase 2 Anaphase 2 Telophase 2 Cytokinesis – 4 Gametes
- 46. At the endof Meiosis the individual Gamete cell has divided from one cell to four. Males produce 4 viable sperm. Females produce 1 viable egg and 3 non functioning polar bodies.
- 47.
- 48. Meiosis ensures that all living organisms willmaintain both Genetic Diversity and Genetic Integrity