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Cell Reproduction

Cell Reproduction. Homework!. www.cellsalive.com Complete the mitosis and meiosis sheets. Cells Division Introductory Video. The Chromosome. During cell division the cell’s DNA is coiled compactly into a CHROMOSOME Each chromosome is a single DNA molecule

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Cell Reproduction

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  1. Cell Reproduction

  2. Homework! • www.cellsalive.com • Complete the mitosis and meiosis sheets

  3. Cells Division Introductory Video

  4. The Chromosome • During cell division the cell’s DNA is coiled compactly into a CHROMOSOME • Each chromosome is a single DNA molecule • The DNA wraps tightly around a protein called HISTONE (helps maintain the chromosome’s shape)

  5. Breaking Down the Definitions • Chromosome • Histone • Chromatid • Centromere • Chromatin • Sex chromosome • Autosome • Homologous chromosome • Karyotype • Diploid • Haploid • Binary fission • Mitosis • Asexual reproduction • Meiosis • Gamete • Interphase • Cytokinesis • Prophase • Spindle fiber • Metaphase • Anaphase • Telophase • Cell plate • Synapsis • Tetrad • Crossing over • genetic recombination • Independent assortment • Sexual reproduction

  6. Anatomy of a Chromosome • Each half of a chromosome is called a CHROMATID • Chromatids form as the DNA copies itself before cell division • The 2 Chromatids are attached at a point called a CENTROMERE • CHROMATIN=less tightly areas of DNA between cell divisions

  7. Chromosome Numbers • Every species has a certain number of chromosomes in each cell. • Animal chromosomes are either: • Sex Chromosomes—will determine the gender of an organism (X and Y) • Autosomes—all of the other chromosomes • Cells with 2 sets of Chromosomes are DIPLOID • Cells with one set of chromosomes are HAPLOID (sex cells…half the number of chromosomes)

  8. Chromosomes Clip • How many chromosomes does a potato have? • How many chromosomes do Ferns have? • After the video…in your own words why do different organisms have different numbers of chromosomes??

  9. Cell Division (aka Cell Reproduction) in Prokaryotes • Most prokaryotes reproduce by BINARY FISSION • 2 identical cells are produced from one cell • Draw this

  10. Cell Division Eukaryotes • Two types of Cell Division (Reproduction) in Eukaryotes! • Mitosis=new cells with identical genetic material • Meiosis=reduces the number of chromosomes by half for the purpose of eventual reproduction

  11. The Cell Cycle • The CELL CYCLE is the repeating events of the life of a cell. • Interphase is the period between cell divisions

  12. How do little elephants grow up to be BIG elephants?

  13. Three reasons why cells reproduce by asexual reproduction or MITOSIS: 1. Growth 2. Repair 3. Replacement

  14. Mitosis Cycle • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis

  15. 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

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

  17. Prophase 1st step in Mitosis • Mitosis begins (cell begins to divide) • Centrioles (or poles) appear and begin to move to opposite end of the cell. • Spindlefibers form between the poles. Centrioles Sister chromatids Spindle fibers

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

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

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

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

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

  23. Telophase4th step in Mitosis • Two new nucleiform. • Chromosomes appear as chromatin (threadsrather than rods). • Mitosisends. Nuclei Nuclei Chromatin

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

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

  26. Animal Mitosis -- Review

  27. Plant Mitosis -- Review

  28. IPMATC REMEMBER! • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis IP___M___ A___T___ C______

  29. Label it!

  30. Brainpop Mitosis

  31. Mitosis in an Onion

  32. Prophase

  33. Metaphase

  34. Anaphase

  35. TELOPHASE and CYTOKINESIS

  36. Stages of Mitosis Animation

  37. It’s your turn! Identify the stages of mitosis…

  38. Mitosis Dance Video

  39. Onion Tips and Whitefish…

  40. Meiosis – key differences from mitosis • Meiosis reduces the number of chromosomes by half. • Daughter cellsdiffer from parent, and each other. • Meiosis involves two divisions, Mitosis only one. • Meiosis I involves: • Synapsis – homologous chromosomes pair up. Chiasmata form (crossing over of non-sister chromatids). • In Metaphase I, homologous pairs line up at metaphase plate. • In Anaphase I, sister chromatids do NOT separate. • Overall, separation of homologous pairs of chromosomes, rather than sister chromatids of individual chromosome. Meiosis KM

  41. Meiosis I (four phases) • Cell division that reduces the chromosome number by one-half. • four phases: a. prophase I b. metaphase I c. anaphase I d. telophase I

  42. Meiosis • The form of cell divisionby which gametes (sperm or egg cells), with half the number of chromosomes,are produced. • Diploid (2n)  haploid (n) n=# of chromosomes • Meiosis is sexual reproduction. • Two divisions (meiosis I and meiosis II).

  43. Meiosis • Sex cells divide to produce gametes(sperm or egg). • Gametes have half the # of chromosomes. • Occurs only in gonads (testes or ovaries). Male: spermatogenesis Female: oogenesis • Meiosis is similar to mitosis with some chromosomal differences.

  44. Sex ChromosomesThe Sex Chromosomes code for the sex of the offspring.** If the offspring has two “X” chromosomes it will be a female. ** If the offspring has one “X” chromosome and one “Y” chromosome it will be a male. In Humans the “Sex Chromosomes” are the 23rd set XX chromosome - female XY chromosome - male

  45. Y chromosome X chromosome Boy or Girl? The Y Chromosome “Decides”

  46. Interphase I • Similar to mitosis interphase. • Chromosomes replicate (S phase). • Each duplicated chromosome consist of two identical sister chromatids attached at their centromeres. • Centriole pairs also replicate.

  47. Interphase I • Nucleus and nucleolus visible. chromatin nuclear membrane cell membrane nucleolus

  48. Prophase I • Longest and most complex phase (90%). • Chromosomes condense. • Synapsis occurs: homologous chromosomes come together to form a tetrad. • Tetrad is two chromosomes or four chromatids (sister and nonsister chromatids).

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