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Mitosis and Meiosis

Mitosis and Meiosis. Date:. Mitosis. http://www.allthingsscience.com/video/715/Human-Chromosomes http ://learn.genetics.utah.edu/content/begin/tour/. Chromosomes. Tightly packed strands of DNA Different organisms have different numbers of chromosomes For example : Ant = 2

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Mitosis and Meiosis

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  1. Mitosis and Meiosis Date:

  2. Mitosis http://www.allthingsscience.com/video/715/Human-Chromosomes http://learn.genetics.utah.edu/content/begin/tour/

  3. Chromosomes • Tightly packed strands of DNA • Different organisms have different numbers of chromosomes For example: • Ant = 2 • Fruit fly = 8 • Rice = 24 • Cat = 38 • Human = 46 • Potato = 48 • Dog = 78 • Shrimp = 254 http://www.youtube.com/watch?v=eOvMNOMRRm8&feature=related

  4. Mitosis (so middle school!) • Simple cell division • Occurs in somaticcells (regular body cells) when they get too big and need to split in two. • This is how you grow http://video.google.com/videoplay?docid=4045285854844480169#docid=-7204725871954420481

  5. Prophase • Chromosomes must first replicate (make an exact copy of themselves) One chromosome Still one chromosome

  6. Metaphase • The chromosomes make a line down the center

  7. Anaphase • Chromosomes are pulled apart to opposite ends of the cell

  8. Telophase • The cell splits into two genetically identical daughter cells

  9. Onion root mitosis

  10. Thumbs Check I understand it 100% and don’t need anymore examples. I kind of understand it. And could use some more examples. I do not understand what is being taught. I could benefit from it being explained differently and maybe more examples.

  11. Thumbs Check It was explained very well. I understand it well enough to explain it to someone else. It was explained ok. I could explain it to someone else after more examples. It was explained poorly. I would benefit from it being explained differently and more examples.

  12. Quickcheck • Describe the functions of the following organelles: 1. nucleus 2. mitochondria 3. chloroplast 4. ribosome

  13. (Mitosis) • Daughter cells have identical nuclei (exact same DNA). • Daughter cells are diploid (they have a full set of chromosomes)

  14. Quickcheck Describe the process of mitosis and draw a diagram

  15. Meiosis Date: http://learn.genetics.utah.edu/content/begin/tour/

  16. Hook • We go together…

  17. A B • Compare and Contrast • These two diagrams. • What is the same about these two processes? • What is different?

  18. MEIOSIS • The process of cell division that makes • sex cells = GAMETES = sperm and egg cells • The process of double reduction division

  19. Hmmm… Fruit flies normally have 8 chromosomes In each of their regular body cells. If a male sex cell and a female sex cell unite to make a baby fruit fly, how many chromosomes do baby fruit flies have?

  20. MEIOSIS • Occurs only in the sex organs- • male testesand female ovaries

  21. MEIOSIS • Produces 4 daughter cells with different genetic material • Daughter cells have half (1/2) the number of chromosomes as a regular somatic (body) cell http://www.cellsalive.com/meiosis.htm

  22. MEIOSIS • Gametes must have half the number of chromosomes (haploid), so that offspring will have the full set (diploid). haploid + haploid = diploid

  23. Thumbs Check I understand it 100% and don’t need anymore examples. I kind of understand it. And could use some more examples. I do not understand what is being taught. I could benefit from it being explained differently and maybe more examples.

  24. Quickcheck • Where does mitosis occur? • In regular body cells like skin, stomach, brain. These are called somatic cells • Where does meiosis occur? • Only in the sexual reproductive organs- cells from male testes and female ovaries • How many cells are produced from a cell that undergoes mitosis? • two • How many cells are produced from a cell that undergoes meiosis? • four

  25. MEIOSIS Diploid = double # = full set Diploid = 2n Haploid = half # = half set Haploid = n

  26. Quickcheck • 1. If human somatic cells have 46 chromosomes, what is the haploid number? • 23 • 2. What is the diploid number for a cat? (check your notes!) • 38 • 3. What is the haploid number for a cat? • 19 • 4. If a cell from a dog’s lung has 78 chromosomes, how many chromos does her egg cell have? • 39 • 5. Which type of cell is haploid (lung or egg)? • egg

  27. Risk box: • Where do you get your chromosomes? • Why are diploid chromosome numbers always even?

  28. Homologous pairs • You get your chromosomes from your parents- half the number from Mom and half from Dad • Diploid numbers are always even because chromosomes are in pairs- each pair has one chromosome from Mom and one from Dad. • These are called HOMOLOGOUSpairs- they are the same size and shape and carry the same genes

  29. In the first phase of meiosis, HOMOLOGOUS PAIRS line up along the center of the cell, and these pairs are pulled apart. In Mitosis, all chromosomes line up along the center of the cell. Sister chromatids are pulled apart. ((In the second phase of meiosis, chromosomes line up single file along the center and sister chromatids are pulled apart, just like in mitosis))

  30. Watch this: • http://www.youtube.com/watch?v=lJzZ7p-47P8&feature=related

  31. Mitosis

  32. STAGES OF MEIOSIS = PMAT X2 • Before Meiosis starts, DNA replicates and forms duplicate chromosomes Prophase I • Each chromosome pairs with its homologous chromosome to form a tetrad

  33. Crossing Over • Homologous chromosomes exchange (swap) genetic material • http://www.youtube.com/watch?v=op7Z1Px8oO4&feature=related

  34. (STAGES OF MEIOSIS) Metaphase I : • Spindle fibers attach to the chromosomes Anaphase I • the homologous chromosomes are pulled apart

  35. STAGES OF MEIOSIS • Telophase I and Cytokinesis • The cell separates into 2 new cells • Each cell is haploid (only has half the number of chromosomes that the original cell started with)

  36. Thumbs Check I understand it 100% and don’t need anymore examples. I kind of understand it. And could use some more examples. I do not understand what is being taught. I could benefit from it being explained differently and maybe more examples.

  37. Thumbs Check It was explained very well. I understand it well enough to explain it to someone else. It was explained ok. I could explain it to someone else after more examples. It was explained poorly. I would benefit from it being explained differently and more examples.

  38. STAGES OF MEIOSIS • Meiosis II PMAT #2 • Prophase 2: Prepare • Metaphase 2 : The chromosomes line up randomly in the middle of cell • Anaphase 2: The spindle fibers separate the sister chromatids and move them to opposite sides • Telophase 2: 4 new haploid daughter cells are formed http://www.sumanasinc.com/webcontent/animations/content/meiosis.html

  39. J-TPS • Is this a diagram of mitosis or meiosis? • How do you know? • MEIOSIS • Double division • Homologous chromosomes pair up • Crossing over happens • From one diploid cell you get 4 haploid cells

  40. J-TPS • What cells do you think would have to go through division twice to only get half the number of chromosomes?

  41. J-TPS • Which of the following statements correctly describes meiosis? • Cells divide only once during meiosis • Meiosis does not occur in reproductive cells • The cells produced at the end of meiosis are genetically identical to the parent cell • The cells produced at the end of meiosis contain half the number of chromosomes as the parent cell

  42. Fertilization

  43. Fertilization • The union of gametes • Sperm and egg unite or fuse • They become a zygote http://www.youtube.com/watch?v=65BV5dXXxzM

  44. / Describe the steps to Meiosis

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