1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cell Reproduction Chapter 8 Table of Contents Section 1 Chromosomes Section 2 Cell Division Section 3 Meiosis

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Objectives Describe the structure of a chromosome. Identify the differences in structure between prokaryotic chromosomes and eukaryotic chromosomes. Compare the numbers of chromosomes in different species. Explain the differences between sex chromosomes and autosomes. Distinguish between diploid and haploid cells.

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Chromosome Structure Chromosomes are rod-shaped structures made of DNA and protein. In eukaryotes, DNA wraps around proteins called histones to help maintain the compact structure of chromosomes.

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Chromosome Structure Section 1 Chromosomes

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Parts of a Chromosome Section 1 Chromosomes

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Chromosome Structure, continued Chromosomes in prokaryotes are simpler in structure than chromosomes in eukaryotes.

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Comparing Cell Division in Prokaryotes and Eukaryotes Section 1 Chromosomes

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Chromosome Numbers Each species has a characteristic number of chromosomes in each cell.

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Chromosome Numbers of Various Organisms Section 1 Chromosomes

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Chromosome Numbers, continued Sex Chromosomes and Autosomes –Sex chromosomes are chromosomes that determine the sex of an organism. –All of the other chromosomes in an organism are autosomes.

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Sex Chromosomes and Autosomes Section 1 Chromosomes

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Chromosomes Chapter 8 Chromosome Numbers, continued Diploid and Haploid Cells –Cells having two sets of chromosomes are diploid (2n). –Haploid cells (1n) have only one set of chromosomes.

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Karyotype Section 1 Chromosomes

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Objectives Describe the events of cell division in prokaryotes. Name the two parts of the cell that are equally divided during cell division in eukaryotes. Summarize the events of interphase. Describe the stages of mitosis. Compare cytokinesis in animal cells with cytokinesis in plant cells. Explain how cell division is controlled.

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Cell Division in Prokaryotes Cell division is the process by which cells reproduce themselves.

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Cell Division in Prokaryotes, continued Binary fission is the process of cell division in prokaryotes.

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Cell Division in Eukaryotes Cell Cycle –The cell cycle is the repeating set of events in the life of a cell. –The cell cycle consists of cell division and interphase. –Cell division in eukaryotes includes nuclear division, called mitosis, and the division of cytoplasm, called cytokinesis.

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Cell Cycle Introduction Section 2 Cell Division

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Cell Division in Eukaryotes, continued Interphase –Interphase consists of growth (G 1 ), DNA replication, and preparation for cell division (G 2 ).

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Stages of Mitosis Mitosis is divided into stages: prophase, metaphase, anaphase, and telophase. Mitosis results in two offspring cells that are genetically identical to the original cell.

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Stages of Mitosis Section 2 Cell Division

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Mitosis Section 2 Cell Division

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Cytokinesis During cytokinesis in animal cells, a cleavage furrow pinches in and eventually separates the dividing cell into two cells. In plant cells, a cell plate separates the dividing cell into two cells.

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Comparing Cell Division in Plants and Animals Section 2 Cell Division

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Control of Cell Division Cell division in eukaryotes is controlled by many proteins. Control occurs at three main checkpoints.

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Control of the Cell Cycle Section 2 Cell Division

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Section 2 Cell Division

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Division Chapter 8 Control of Cell Division, continued When Control is Lost: Cancer –Cancer may result if cells do not respond to control mechanisms.

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Objectives Compare the end products of meiosis with those of mitosis. Summarize the events of meiosis I. Explain crossing-over and how it contributes to the production of unique individuals. Summarize the events of meiosis II. Compare spermatogenesis and oogenesis. Define sexual reproduction.

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Formation of Haploid Cells Meiosis is a process of nuclear division that reduces the number of chromosomes in new cells to half the number in the original cell. Meiosis produces haploid gametes.

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Formation of Haploid Cells, continued Meiosis is a process of nuclear division that reduces the number of chromosomes in new cells to half the number in the original cell. Meiosis leads to four haploid cells (gametes) rather than two diploid cells as in mitosis.

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Meiosis I Meiosis I includes prophase I, metaphase I, anaphase I, and telophase I. Crossing-over, which is when portions of homologous chromosomes exchange genetics material, occurs during prophase I and results in genetic recombination.

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Tetrads and Crossing-over of Genetic Material Section 3 Meiosis

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Meiosis II Meiosis II includes prophase II, metaphase II, anaphase II, and telophase II. Four new haploid cells result.

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Section 3 Meiosis Stages of Meiosis

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Stages of Meiosis, continued Section 3 Meiosis

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Visual Concept Comparing Meiosis and Mitosis Section 3 Meiosis

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Development of Gametes Spermatogenesis is the process by which sperm cells are produced. Oogenesis is the process that produces mature egg cells.

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Meiosis in Male and Female Animals Section 3 Meiosis

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Meiosis Chapter 8 Sexual Reproduction Sexual reproduction is the formation of offspring through meiosis and the union of a sperm and an egg. Offspring produced by sexual reproduction are genetically different from the parents.

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 8 Click below to watch the Visual Concept. Sexual Reproduction Section 3 Meiosis