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Cell Reproduction

Cell Reproduction. Chromosomes Cell Division. Chromosomes. Chromatin Structure Chromosome Structure Chromosome Condensation Sister Chromatids. Learning Objectives. TSW … Distinguish between chromatin & condensed chromosomes Describe the location & structure of a chromosome

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Cell Reproduction

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  1. Cell Reproduction • Chromosomes • Cell Division

  2. Chromosomes • Chromatin Structure • Chromosome Structure • Chromosome Condensation • Sister Chromatids

  3. LearningObjectives • TSW … • Distinguish between chromatin & condensed chromosomes • Describe the location & structure of a chromosome • Describe chromosome condensation • Explain what sister chromatids are

  4. 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

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

  6. 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

  7. Roles of Cell Division • Asexual Reproduction • prokaryotes • protistans • fungi • Growth & Development • multicellular organisms • Repair & Regeneration • multicellular organisms • plants • primitive animals

  8. Growth & Development Fertilized egg Multicellular Organisms Ist division Early embryo Late embryo Fetus Toddler Young child Young adult

  9. Tissue Renewal Multicellular Organisms bone marrow stem cells

  10. Tissue Repair

  11. 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

  12. Cell Division • The Cell Cycle • Interphase • Mitosis • Cytokinesis

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

  14. 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

  15. Mitotic Cell Cycle: Overview “mitotic phase” = division of the cell: mitosis cytokinesis • Major Stages of Mitotic Cell Division: • Interphase • Divided into 3 phases • Mitosis (M phase) • Divided into 4 main phases • Phases often subdivided • Cytokinesis (M phase) • Animal cell process • Plant cell process

  16. 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

  17. DNA Replication

  18. Interphase

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

  20. Phases of Mitosis • Prophase • Prometaphase • Metaphase • Anaphase • Telophase Proud Pittsburgh Made A Touchdown A Pneumonic Aide!

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

  22. Chromosome & Sister Chromatids

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

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

  25. 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

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

  27. Spindle Apparatus

  28. Centrosomes centrosome

  29. Kinetochore Structure

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

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

  32. Kinetochore Function

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

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

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

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

  37. Cytokinesis • Division of the Cytoplasm: • Begins duringearly telophase • Finishes immediately after telophase • Daughter cells separated by different mechanisms in plants & animals

  38. Cytokinesis

  39. Cytokinesis • Cleavage furrow formation: animal cells • microfilaments attached to cell membrane shorten • Cell ispinched in two • Daughter nuclei separated • Results in 2 daughter cells with identical genetic material

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

  41. Mitotic Cell Division:Time Lapse • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • ASF Video plays about 52 sec

  42. Review of Mitosis & Cytokinesis • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • MOV Video plays about 30 sec

  43. Mitosis Review

  44. Mitosis Review

  45. Regulation of Mitosis

  46. Cancer

  47. Cells & Human Biology • To View Video: • Move mouse cursor over slide title-link • When hand appears, click once • ASX Video plays about 16 min

  48. Compound Light Microscope Arm Base

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