1. How Cells Reproduce Power Point Lectures for Biology: Concepts and Applications, 6e Cecie Starr Copyright 2006 Thomson Brooks/Cole

2. Mitosis somatic cells meiosis germ cells chromosome Mitosis somatic cells meiosis germ cells chromosome sister chromatids histones nucleosome centromere kinetochores cell cycle interphase G1, S, G2, M chromosome number sister chromatids histones nucleosome centromere kinetochores cell cycle interphase G1, S, G2, M chromosome number diploid number prophase metaphase anaphase telophase bipolar mitotic spindle microtubules centrioles centrosome cytoplasmic division cytokinesis cleavage cleavage furrow diploid number prophase metaphase anaphase telophase bipolar mitotic spindle microtubules centrioles centrosome cytoplasmic division cytokinesis cleavage cleavage furrow cell plate formation growth factors kinases oncogenes neoplasms benign cancers malignant metastasis cell plate formation growth factors kinases oncogenes neoplasms benign cancers malignant metastasis

3. 1.Understand the factors that cause cells to reproduce. 2.Understand what is meant by cell cycle and explain where mitosis fits into the cell cycle. 3.Be able to describe each phase of mitosis. 4.Explain how the apportioning of cytoplasm to the daughter cells follows mitosis, which is a nuclear event. 5.List some of the problems in cell division when control is lost.

4. What instructions are necessary for inheritance? What instructions are necessary for inheritance? How are those instructions duplicated for distribution into daughter cells? How are those instructions duplicated for distribution into daughter cells? By what mechanisms are instructions parceled out to daughter cells? By what mechanisms are instructions parceled out to daughter cells?

5. Parents produce a new generation of cells or multi-celled individuals like themselves Parents produce a new generation of cells or multi-celled individuals like themselves Parents must provide daughter cells with hereditary instructions, encoded in DNA, and enough metabolic machinery to start up their own operation Parents must provide daughter cells with hereditary instructions, encoded in DNA, and enough metabolic machinery to start up their own operation

6. Eukaryotic organisms – Mitosis – Meiosis Prokaryotic organisms – Prokaryotic fission

7. Multicelled organisms Multicelled organisms – Growth – Cell replacement Some protistans, fungi, plants, animals Some protistans, fungi, plants, animals – Asexual reproduction

8. Functions only in sexual reproduction Functions only in sexual reproduction Precedes the formation of gametes (sperm and eggs) or spores Precedes the formation of gametes (sperm and eggs) or spores

9. A DNA molecule & attached proteins A DNA molecule & attached proteins Duplicated in preparation for mitosis Duplicated in preparation for mitosis

10. core of histone fiber centromere (restricted region) supercoiling of the coiled loops of DNA beads on a string DNA double helix a A duplicated human chromosome in its most condensed form. b At times when a chromosome is most condensed, the proteins associated with it interact in ways that package loops of already coiled DNA into “supercoils.” c At a deeper level of structural organization, the chromosomal proteins and DNA are organized as a cylindrical fiber. d Immerse a chromosome in saltwater and it loosens to a beads-on-a-string organizationWhat appears to be a “string” is one DNA molecule. Each “bead” is a nucleosome. nucleosome Fig. 8-3, p.127

11. Fig. 8-14, p.137

12. Each chromosome and its copy stay attached to each other as sister chromatids until late in the nuclear division process Each chromosome and its copy stay attached to each other as sister chromatids until late in the nuclear division process Attach at the centromere Attach at the centromere

13. A nucleosome consists of part of a DNA molecule looped twice around a core of histone proteins A nucleosome consists of part of a DNA molecule looped twice around a core of histone proteins

14. Cycle starts when a new cell forms Cycle starts when a new cell forms During cycle, cell increases in mass and duplicates its chromosomes During cycle, cell increases in mass and duplicates its chromosomes Cycle ends when the new cell divides Cycle ends when the new cell divides

15. Fig. 8-4, p.128

16. Usually longest part of the cycle Usually longest part of the cycle Cell increases in mass Cell increases in mass Number of cytoplasmic components doubles Number of cytoplasmic components doubles DNA is duplicated DNA is duplicated

18. Once S begins, the cycle automatically runs through G2 and mitosis Once S begins, the cycle automatically runs through G2 and mitosis The cycle has a built-in molecular brake in G1 The cycle has a built-in molecular brake in G1 Cancer involves a loss of control over the cycle, malfunction of the “brakes” Cancer involves a loss of control over the cycle, malfunction of the “brakes”

19. Table 8.1 Cell Division Mechanisms Mechanisms Functions Table 8-1, p.126 Mitosis, cytoplasmic division Meiosis, cytoplasmic division Prokaryotic fission In all multicelled eukaryotes, the basis of the following: 1. Increases in body size during growth. 2. Replacement of dead or worn-out cells. 3. Repair of damaged tissues. In single-celled and many multicelled eukaryotes, also the basis of asexual reproduction. In single-celled and multicelled eukaryotes, the basis of sexual reproduction; precedes gamete or spore formation (Chapter 9). In bacteria and archaea only, the basis of asexual reproduction (Section 19.1).

20. mitosis, cytoplasmic division a Two of the chromosomes (unduplicated) in a parent cell at interphase b The same two chromosomes, now duplicated, in that cell at interphase, prior to mitosis c Two chromosomes (unduplicated) in the parent cell’s daughter cells, which both start life in interphase Fig. 8-5b, p.129

21. chromosomes (unduplicated) in parent cell at interphase same chromosomes (duplicated) in interphase prior to mitosis mitosis, cytoplasmic division chromosome (unduplicated) in daughter cell at interphase chromosome (unduplicated) in daughter cell at interphase Fig. 8-5b, p.129

22. microtubule of bipolar spindle p.129

23. Mitosis pair of centrioles nuclear envelop chromosomes b EARLY PROPHASEc LATE PROPHASE d TRANSITION TO METAPHASE Mitosis begins. The DNA and its associated proteins have started to condense. The two chromosomes color-coded purple were inherited from the female parent. The other two (blue) are their counterparts., inherited from the male parent. Chromosomes continue to condense. New microtubules become assembled. They move one of the two pairs of centrioles to the opposite end of the cell. The nuclear envelope starts to break up. Now microtubules penentrate the nuclear region. Collectively, they form a bipolar spindle apparatus. Many of the spindle microtubules become attatched to the two sister chromatids of each chromosome. a Cell at Interphase The cell duplicates its DNA, prepares for nuclear division Fig. 8-6a, p.130

24. 1 Mitosis is over, and the spindle is now disassembling. 2 At the former spindle equator, a ring of micro- filaments attached to the plasma membrane contracts. 3 As its diameter shrinks, it pulls the cell surface inward. 4 Contractions continue; the cell is pinched in two. Fig. 8-7a, p.132

25. Usually occurs between late anaphase and end of telophase Usually occurs between late anaphase and end of telophase Two mechanisms Two mechanisms – Cleavage (animals) – Cell plate formation (plants)

26. Two daughter nuclei Two daughter nuclei Each with same chromosome number as parent cell Each with same chromosome number as parent cell Chromosomes in unduplicated form Chromosomes in unduplicated form

27. New microtubules are assembled New microtubules are assembled One centriole pair is moved toward opposite pole of spindle One centriole pair is moved toward opposite pole of spindle Nuclear envelope starts to break up Nuclear envelope starts to break up

28.  Spindle forms  Spindle microtubules become attached to the two sister chromatids of each chromosome

29. All chromosomes are lined up at the spindle equator All chromosomes are lined up at the spindle equator Chromosomes are maximally condensed Chromosomes are maximally condensed

30. Sister chromatids of each chromosome are pulled apart Sister chromatids of each chromosome are pulled apart Once separated, each chromatid is a chromosome Once separated, each chromatid is a chromosome

31. Chromosomes decondense Chromosomes decondense Two nuclear membranes form, one around each set of unduplicated chromosomes Two nuclear membranes form, one around each set of unduplicated chromosomes

32. cell plane forming 1 As mitosis ends, vesicles cluster at the spindle equator. They contain materials for anew primary cell wall. 2 Vesicle membranes fuse. The wall material is sandwiched between two new membranes that lengthen along the plane of a newly forming cell plate. 3 Cellulose is deposited inside the sandwich. In time, these deposits will form two cell walls. Others will form the middle lamella between the walls and cement them together. 4 A cell plate grows at its margins until it fuses with the parent cell plasma membrane. The primary wall of growing plant cells is still thin. New material is deposited on it. Fig. 8-7b, p.132

33. cell wall former spindle equator cell plate vesicles converging Stepped Art Fig. 8-7b, p.132

34. ring of microfilaments midway between the two spindle poles, in the same plane as the spindle equator Fig. 8-8, p.133

35. Prophase of whitefish cell mitosis. LM X360. Credit: © Carolina Biological 214 212

36. Metaphase of whitefish cell mitosis. The metaphase stage follows prophase. During this time the chromosomes align at the metaphase plate. LM X360. Credit: © Carolina Biological 214 213

37. Anaphase of whitefish cell mitosis. During this stage the paired chromosomes separate and being to move to opposite ends of the cell. LM X360. Credit: © Carolina Biological 214

38. Telophase of whitefish cell mitosis. During telophase the chromosomes are barricaded off into two distinct nuclei in the emerging daughter cells. LM X360. Credit: © Carolina Biological 214 215

39. Daughter cells created as a result of mitosis. LM X360. Credit: © Carolina Biological 214 216

40. Onion root tip mitosis - Interphase stage. Credit: © Carolina Biological 214 264

41. Onion root tip mitosis - Prophase stage. Credit: © Carolina Biological 214 265

42. Onion root tip mitosis - Metaphase stage. Credit: © Carolina Biological 214 266

43. Onion root tip mitosis - Early anaphase stage. Credit: © Carolina Biological 214 267

44. Onion root tip mitosis - Late anaphase stage. Credit: © Carolina Biological 214 268

45. Onion root tip mitosis - Telophase stage. Credit: © Carolina Biological 214 269

46. Onion root tip mitosis - Daughter cells. Credit: © Carolina Biological 214 270

47. Confocal image of cells at various stages of mitosis. The markers are microtubules (in red), DNA (in blue) and the Golgi apparatus (which temporarily fragments during mitosis, in green). Credit: © Thomas Deerinck 900 084

48. Confocal image of dividing cell. The markers are mitotic spindle (red), chromosomes (blue), and peroxisomes (green). Credit: © Thomas Deerinck 900 085

49. Fig. 8-9, p.133

50. Fig. 8-10a, p.134

51. Fig. 8-10b, p.134

52. Fig. 8-11, p.134

53. benign tumormalignant tumor 1 Cancer cells slip of out their home tissue 3 Cancer cells creep or tumble along inside blood vessels, then leave the bloodstream the same way they got in. They start new tumors in new tissues. 2 The metastasizing cells become attached to the wall of a blood or lymph vessel. They secrete digestive enzymes onto it. Then they cross the wall at the breach. Fig. 8-12, p.135

54. Fig. 8-13a, p.135

55. Fig. 8-13b, p.135

56. Fig. 8-13c, p.1135

57. p.136