1. Standard Biology Chapter 22 Cellular Reproduction
Section 22:1 Mitosis

2. Mitosis One cell divides and divides to form 3 trillion cells (you)
Process of cell reproduction by which 2 new identical cells are formed from one parent cell

3. Mitosis Needed for growth, repair, and replacement of body parts
Growth: new muscle
Repair: broken bone need new bone cells
Replacement: new blood cells when have loss of blood

4. Mitosis
All body cells are formed by mitosis (body cells are all cells that are not sex cells)

5. Different Cells Have Different Life Span
Cell Type
Brain Cell
Red Blood Cell
Platelets
Stomach Lining
Liver Cells
Intestine Lining
Skin
Life Span
30-50 years
120 days
10 days
2 days
200 days
3 days
20 days

6. Mitosis Mitosis continues your entire life
Cells go through mitosis at different rates, some are slow and some are fast

7. Cell Cycle
Most of the time cells are not dividing, they are just growing and doing their job
Interphase: time between mitosis when cells grow, do their job and get ready for mitosis by:
Doubling chromosomes get sister chromatids
Making more cell parts (mitochondria…)

8. Steps of Mitosis Prophase Sister chromatids thicken so can be seen
Nuclear membrane disappears
Centrioles (animals only) move away from each other
Spindle fibers form between centrioles

9. Prophase Chromosome (two sister chromatids) Centriole Spindle fiber
Nuclear membrane (disintegrating)

10. Prophase

11. Steps of Mitosis Metaphase
Sister chromatids are hooked to spindle fiber
Sister chromatids are in center of cell

12. Metaphase

13. Metaphase

14. Steps of Mitosis
Anaphase
Sister chromatids are pulled apart

15. Anaphase

16. Anaphase
PLANT
ANIMAL

17. Steps of Mitosis Telophase Each chromatid forms a nucleus
Nuclear membrane forms around the 2 new nuclei
Spindle fibers disappear
Chromatids thin and can’t be seen
Cell cytoplasm usually divides (cytokinesis)

18. Telophase

19. Telophase After Telophase the 2 new cells are in interphase
Cytokinesis is the division of the cell contents forming two new cells

20. Results of Mitosis
Results of mitosis: get 2 new cells that are genetically identical (same chromosome) but smaller in size

21. Differences between mitosis in plants and animals
1. Plants don’t have centrioles, animals cells do; both have spindle fibers
Centrioles

22. Differences between mitosis in plants and animals
2. Plants have cell wall so must add more cell wall between new cells not just pinch in cytoplasm to divide it

24. Standard Biology Chapter 22 Cellular Reproduction
Section 22:2 Meiosis

25. Meiosis
Sex cells (eggs and sperm) are produced by a process different from mitosis
Meiosis: cell divides twice to form 4 new cells each with ½ the number of chromosomes
Start with one body cell end with 4 sex cells

26. Meiosis
Interphase happens just like mitosis, chromosomes are doubled

27. Steps of Meiosis: Meiosis I
Prophase I
Sister chromatids shorten and thicken
Nuclear membrane disappears
Centrioles move to opposite ends of cell
Spindle fibers form
Two pair of sister chromatids (matching chromosomes) come together; get tetrads; exchange genetic material

28. Steps of Meiosis: Meiosis I
Prophase I
Homologous Chromosomes
(tetrads)

29. Steps of Meiosis: Meiosis I
Metaphase I
Tetrads in center of cell
Spindle fibers attached to chromosomes

30. Steps of Meiosis: Meiosis I
Metaphase I
Tetrads

31. Steps of Meiosis: Meiosis I
Anaphase I
A pair of sister chromatids gets pulled away from the other pair of sister chromatids

32. Steps of Meiosis: Meiosis I
Telophase I
Cell divides
Nuclear membrane DOES NOT REFORM

33. Steps of Meiosis: Meiosis II
Prophase II and Metaphase II
Spindle fibers attach to sister chromatids
Sister chromatids are in middle of cell
Metaphase II
Prophase II

34. Steps of Meiosis: Meiosis II
Anaphase II and Telophase II
Sister chromatids are pulled apart
Nuclear membrane reforms
Anaphase II
Telophase II

35. Result of Meiosis
Results of Meiosis: end with 4 sex cells that have ½ of the chromosomes as parent cell

36. Sperm, Egg, and Fertilization Comparison of Sperm and Egg
How Alike
sex cells
formed by meiosis
½ number of chromosomes
humans develop at puberty
How Different
egg larger than sperm
sperm has tail, can move
sperm form in male testes
eggs form in female ovary
only get 1 egg in meiosis
get 4 sperm in meiosis

37. Sperm, Egg, and Fertilization
Formation of Polar Bodies
Happens in meiosis to produce eggs
Cell division is not equal, most of cytoplasm goes to one cell
Polar body is the cell formed with little cytoplasm
Polar bodies do not form eggs, they die

38. Sperm, Egg, and Fertilization
Formation of Polar Bodies

39. Sperm, Egg, and Fertilization
Joining of sperm and egg
Chromosomes come together and pair up forming a new organism with the correct number of chromosomes
New organism has ½ chromosomes form mother and ½ chromosomes from father

40. Sperm, Egg, and Fertilization

41. Standard Biology Chapter 22 Cellular Reproduction
Section 22:3 Changes in the Rate of Mitosis

42. Changes that Occur in the Human Body with Age
Body System
Trait
20 Year Old
70 Year Old
Skin/Nails
Rate of fingernail growth
1mm/
week
0.6mm/week
Nervous
Reaction Time
0.8 sec
0.95 sec
Circulatory
Pumping action of heart
3.7 L/ min
2.9 L/ min
Memory
14 of 24 words recalled
7 of 24 words recalled

43. Changes that Occur in the Human Body with Age
Body System
Trait
20 Year Old
70 Year Old
Respiratory
Lung volume per breath
5.5 L/ inhalation
3.0 L/
inhalation
Muscular
% body fat (male)
15%
30%

44. Aging Becoming older All living things age Loss of hair Wrinkled skin
Bone calcium loss
Cells wear out faster than they are replaced or are not replaced (mitosis slows down)
Muscle cells (including heart) are not replaced, each cell can get bigger but no new cells

45. Aging

46. Cancer Healthy cells: regular rate of mitosis
Cancer: too fast rate of mitosis
Shape of cell and nuclei change
Abnormal cells crowd out normal cells
Fig p. 478

49. Causes of Cancer Environmental factors
Chemicals: chewing tobacco (mouth)
Smoking tobacco (lung)

50. Causes of Cancer Environmental factors Radiation: UV light (skin)
Viruses: (warts and cervical cancer)
Diet

51. Causes of Cancer Genetic Factors Runs in a family
Locate the gene may be able to prevent the cancer
Many cancers thought to be a combination of environmental and genetic factors