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Cell Reproduction

Cell Reproduction

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Cell Reproduction

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  1. Cell Reproduction • Chromosomes • Cell Division • Meiotic Cell Cycle

  2. Mitosis Introduction • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • ASX Video plays about 14-1/4 min • A Video Quiz is included in the presentation

  3. Chromosomes • Chromosome Structure • Chromosome Numbers • Sex Chromosomes & Autosomes • Diploid & Haploid Cells • Karyotyping

  4. LearningObjectives • TSW … • Describe the structure of a chromosome • Compare prokaryotic chromosomes w/ eukaryotic chromosomes • Explain the difference btw/ sex chromosomes & autosomes • Give examples of haploid & diploid cells

  5. Chromosomes • Chromosome Structure • DNA – deoxyribonucleic acid • Proteins • Histones • Serve as “spools” for long DNA molecule • Maintain chromosome shape • Nonhistone proteins • Control regional activity of DNA • Chromosome Function • Genetic Code – hereditary material When NOT involved in cell division, chromosomes exist as chromatin – a mixture of DNA & proteins w/in the nucleus

  6. Chromosome Condensation histones • coiling around histones • coiling into supercoils • further coiling into visible structures (light microscope)

  7. Chromosome & Sister Chromatids • Terminology: • centromere • constricted region of chromosome • sister chromatids are joined here • kinetochore – structure w/in centromere where spindle microtubules attach to sister chromatids • 1 kinetochore for each chromatid

  8. ChromosomeNumbers • Chromosome Number • Characteristic for each species • 2 different species may have the same chromosome number • Chimpanzees & gorillas w/48 – both apes; closely related • Potatoes & gorillas w/ 48 – not closely related

  9. Types of AnimalChromosomes • Sex Chromosomes(1 pair = 2 in humans) • Chromosomes that carry genes for sexual expression • Determine the sex of an organism • May carry genes for other characters • Human Sex Chromosomes – “X” & “Y” • XX= female • XY= male • Autosomes(22 pairs = 44 in humans) • Carry genes for most characters

  10. HomologousChromosomes • Karyotype– displays homologues • Homologous Chromosomes • chromosome pairs of the same length, centromere position, and staining pattern that posses genes for the same characters • one homologue is inherited from the organism’s father • one homologue is inherited from the organism’s mother

  11. Homologous Chromosomes

  12. ChromosomeSets • Haploid Cells • 1 setof chromosomes • Symbol = n • In humans, n = 23 • In fruit fly, n = 4 • Diploid Cells • 2 setsof chromosomes • Symbol = 2n • In humans, 2n = 46 • In fruit fly, 2n = 8

  13. Karyotype Q: Is this a karyotype of amaleor afemale? • Homologous Chromosomes (a.k.a., homologues) • Same size & shape • Centromere in same position • Same staining characteristics • Carry genes for same characteristics • Karyotype • Photomicrograph of the chromosomes from a dividing cell • Can be used to determine genetic defects or sex of organism Sex Chromosomes

  14. Karyotyping • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • ASF Video plays about 3 min

  15. Cell Division • Cell Division in Prokaryotes • Cell Division in Eukaryotes • The Cell Cycle • Interphase • Mitosis • Cytokinesis

  16. LearningObjectives • TSW … • Describe the events of binary fission • Describe each phase of the cell cycle • Summarize the phases of mitosis • Compare cytokinesis in plant & animal cells

  17. Binary Fission Note: no nucleus; no mitosis 1 2 3

  18. Binary Fission& Asexual Reproduction • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • ASX Video plays about 1 min

  19. EukaryoticCell Division • Mitotic Cell Division • One diploid (2n) parent cell  two diploid (2n) daughter cells • Genetic material in daughter cells is identical • Occurs in asexual reproduction of unicellular eukaryotes & addition of new cells to tissues/organs

  20. EukaryoticCell Division • Meiotic Cell Division • One diploid (2n) parent cell  four diploid (2n) daughter cells • Genetic material in daughter cells is NOT identical • Occurs in sexual reproduction of multicellular eukaryotes

  21. Mitotic Cell Cycle: Overview • Major Stages of Mitotic Cell Division: • Interphase • Divided into 3 phases • Cell Division • Mitosis (M phase) • Division of nucleus • Divided into 4-5 main phases • Cytokinesis • Division of cytoplasm “mitotic phase” = division of the cell: mitosis cytokinesis

  22. The Cell Cycle Movie • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 1 min

  23. Interphase:Phases of Interphase • Preparatory Stage: • G1 phase • cell growth; organelles duplicate; mitochondria & chloroplasts self-replicate • S phase • DNA replication • G2 phase • enzymes & other materials necessary for division synthesized; cell growth continues • G0phase • Cell exists the cell cycle; organelles duplicate • EX: mature nerve cells of CNS

  24. DNA Replication

  25. Interphase

  26. Interphase • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 25 sec

  27. Mitosis:Phases of Mitosis • Prophase • Metaphase • Anaphase • Telophase • “Philadelphia” • or whoever! • Made • A • Touchdown A Pneumonic Aide!

  28. Mitosis: Prophase • Division of the Nucleus: • Early Prophase • chromosomes condense as sister chromatids • nucleoli dissolve • spindle apparatus begins to form from centrosomes (MTOC)

  29. Cytoskeletal Elements of Division • Terminology: • Centrosome • microtubule organizing center (MTOC) • synthesizes mitoticspindle • Centrioles • animal cells only • 2/centrosome • 9 sets of triplet microtubules arranged in ring

  30. Chromosome & Sister Chromatids

  31. Mitosis:Early Prophase • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 20 sec

  32. Mitosis: Late Prophase • Division of the Nucleus: • Late Prophase (Prometaphase) • nuclear envelope fragments • spindle stretches across cell • spindle microtubules: • Kinetochore fibers – some attach to chromosomes at kinetochores • Polar fibers – other microtubules stretch toward poles

  33. Mitosis:Late Prophase (Prometaphase) • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 20 sec

  34. Mitosis: Metaphase • Division of the Nucleus: (cont) • Metaphase • spindle across cell w/ centrosomes at opposite poles • chromosomes line up acrossmetaphaseplate [cell equator] • attached to “kinetochore fibers” spindle microtubules • “polar” microtubules span cell from equator to each pole

  35. Spindle Apparatus

  36. Centrosomes centrosome

  37. Kinetochore Structure

  38. Mitosis:Metaphase • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 12 sec

  39. Mitosis: Anaphase • Division of the Nucleus: (cont) • Anaphase • centromeres separate • sister chromatids move to opposite cell poles as kinetochore fibers shorten • Polar fibers lengthen

  40. Kinetochore Function

  41. Mitosis:Anaphase • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 22 sec

  42. Mitosis:Anaphase Time Lapse • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 9 sec

  43. Mitosis: Early Telophase • Division of the Nucleus: (cont) • Early Telophase • polar fibers lengthen stretching cell • chromosomes (formerly sister chromatids) reach opposite poles of cell

  44. Mitosis: Late Telophase • Division of the Nucleus: (cont) • Late Telophase • daughter nuclear envelopes reform • daughter nucleoli reform • chromosomesdecondense to chromatin

  45. Mitosis:Telophase • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 20 sec

  46. Cytokinesis • Division of the Cytoplasm: • Begins during late anaphase to early telophase • Finishes immediately after telophase • Daughter cells separated by different mechanisms in plants & animals

  47. Cytokinesis

  48. Cytokinesis • Cleavage furrow formation: animal cells • microfilaments attached to cell membrane & shorten to pinch cell in two: separating daughter nuclei • Cell plate formation: plant cells • vesicles produced from Golgi apparatusform and fuse btw/ daughter nuclei

  49. Animal Cell Cytokinesis Cleavage Furrow Formation

  50. Plant Cell Cytokinesis Cell Plate Formation