Biology is the only subject in which multiplication is the same thing as division …

1. Biology is the only subject in which multiplication is the same thing as division…

2. The Cell Cycle:Cell Growth, Cell Division

3. You started as a cell smaller than a period at the end of a sentence… Where it all began…

4. And now look at you… How did you get from there to here? How did you get from there to here?

5. Going from egg to baby…. the original fertilized egg has to divide… and divide… and divide… and divide… Getting from there to here…

6. For________________ • asexual reproduction • one-celled organisms • For________________ • from fertilized egg to multi-celled organism • For_________________ • replace cells that die from normal wear & tear or from injury amoeba Why do cells divide?

7. The rate of cell division varies with the need for those types of cells. Cells divide at different rates. • Some cells are unlikely to divide (G0).

8. ____________ • chromosomes • DNA • ______________ • centrioles • in animals • microtubule spindle fibers Making new cells

9. DNA chromosome histone protein nuclear pores nuclear pore nucleolus nuclear envelope • Function • ______________ DNA • Structure • nuclear envelope • double membrane • membrane fused in spots to create _________ • allows large macromolecules to pass through Nucleus What kind of molecules need to pass through?

10. DNA chromosome histone protein • Watch the following animation http://www.youtube.com/DNALearningCenter#p/f/3/9kQpYdCnU14 Packaging DNA

12. Function • structural ______________ • maintains shape of cell • provides anchorage for organelles • protein fibers • microfilaments, intermediate filaments, microtubules • ________________ • cell locomotion • cilia, flagella, etc. • ________________ • organizes structures & activities of cell Cytoskeleton

13. actin • microtubule • nuclei Cytoskeleton

14. Cell ________________ • in animal cells, pair of centriolesorganize microtubules • ____________ ______________ • guide chromosomes in __________ Centrioles

15. End of the Tour

16. What is passed on to daughter cells? • exact copy of genetic material = ______ • _______________ • organelles, cytoplasm, cell membrane, enzymes • ________________ Getting the right stuff chromosomes (stained orange)in kangaroo rat epithelial cell notice cytoskeleton fibers

17. I.P.M.A.T. interphase prophase (pro-metaphase) cytokinesis Overview of mitosis metaphase anaphase telophase

18. __________ of cell life cycle • cell doing its “everyday job” • produce RNA, synthesize proteins/enzymes • prepares for duplication if triggered I’m working here! Time to divide& multiply! Interphase

19. Cell has a “life cycle” cell is formed from a mitotic division cell grows & matures to divide again cell grows & matures to never divide again G1, S, G2, M liver cells G1G0 Cell cycle epithelial cells,blood cells, stem cells brain / nerve cells muscle cells

20. G0 signal to divide • Divided into 3 phases: • G1= 1stGap (Growth) • cell doing its “everyday job” • cell grows • S= DNA Synthesis • copies chromosomes • G2 = 2ndGap (Growth) • prepares for division • cell grows (more) • produces organelles,proteins, membranes Interphase

21. green = key features • Nucleus well-defined • DNA loosely packed in long chromatin fibers • ______________ for mitosis • ___________________chromosome • DNA & proteins • _________________ proteins & organelles Interphase

22. Synthesis phase of Interphase • dividing cell ______________ DNA • must separate DNA copies correctly to 2 daughter cells • human cell duplicates ~3 meters DNA • each daughter cell gets complete identical copy • error rate = ~1 per 100 million bases • 3 billion base pairs in mammalian genome • ~30 errors per cell cycle • mutations (to somatic (body) cells) S phase: Copying / Replicating DNA

23. ACTGGTCAGGCAATGTC DNA • DNA is organized in ___________________ • double helix DNA molecule • wrapped around _________ proteins • like thread on spools • DNA-protein complex =__________________ • organized into long thin fiber • condensed further during mitosis histones chromatin Organizing DNA double stranded chromosome duplicated mitotic chromosome

24. After DNA duplication, chromatin ____________ • coiling & folding to make a smaller package mitotic chromosome DNA chromatin Copying DNA & packaging it…

25. double-strandedmitotic humanchromosomes

26. homologous chromosomes homologous chromosomes sister chromatids • Duplicated chromosome • 2 sister chromatids • narrow at ____________ • contain identical copies of original DNA Mitotic Chromosome single-stranded homologous = “same information” double-stranded

27. Each chromatid has own kinetochore proteins • microtubules attach to kinetochore proteins Kinetochore

28. Dividing cell’s DNA between 2 daughter nuclei • “dance of the chromosomes” • 4 phases • prophase • metaphase • anaphase • telophase Mitosis

29. green = key features • Chromatin condenses • visible chromosomes • chromatids • ________________ move to opposite poles of cell • animal cell • Protein fibers cross cell to form mitotic ________________ • microtubules • actin, myosin • coordinates movement of chromosomes • Nucleolus disappears • Nuclear membrane breaks down Prophase

30. green = key features • Prometaphase • spindle fibersattach to centromeres • creating ________________ • microtubules attach at kinetochores • connect centromeres to centrioles • chromosomes begin moving Transition to Metaphase

31. green = key features • Chromosomes align along middle of cell • _________________ plate • meta = middle • spindle fibers coordinate movement • helps to ensure chromosomes separate properly • so each new nucleus receives only 1 copy of each chromosome Metaphase

33. green = key features • Sister chromatids separate at kinetochores • move to opposite poles • pulled at centromeres • pulled by motor proteins “walking”along microtubules • actin, myosin • increased production of ATP by mitochondria • Poles move farther apart • polar microtubules lengthen Anaphase

34. In anaphase, proteins holding together sister chromatids are inactivated • separate to become individual chromosomes Separation of chromatids 1 chromosome 2 chromatids 2 chromosomes single-stranded double-stranded

35. Kinetochores use motor proteins that “walk” chromosome along attached microtubule • microtubule shortens by dismantling at kinetochore (chromosome) end Chromosome movement

36. green = key features • Chromosomes arrive at opposite poles • daughter nuclei form • nucleoli form • chromosomes disperse • no longer visible under light microscope • Spindle fibers disperse • Cytokinesis begins • cell division Telophase

37. Animals • constriction belt of ___________ microfilaments around equator of cell • ________________ ________________forms • splits cell in two • like tightening a draw string Cytokinesis

38. Cytokinesis in Animals (play Cells Alive movies here)

39. Mitosis in whitefish blastula

40. Mitosis in animal cells

41. Plants • _____________forms • vesicles line up at equator • derived from Golgi • vesicles fuse to form 2 cell membranes • new cell wall laid down between membranes • new cell wall fuses with existing cell wall Cytokinesis in Plants

42. Cytokinesis in plant cell

43. Mitosis in plant cell

44. onion root tip

45. Any Questions??