Table of Contents

1. Chapter 8 Cell Reproduction Table of Contents Section 1 Chromosomes Section 2 Cell Division Section 3 Meiosis

2. Section 1 Chromosomes Chapter 8 Objectives • Describethe structure of a chromosome. • Identifythe differences in structure between prokaryotic chromosomes and eukaryotic chromosomes. • Comparethe numbers of chromosomes in different species. • Explainthe differences between sex chromosomes and autosomes. • Distinguishbetween diploid and haploid cells.

3. Section 1 Chromosomes Chapter 8 Chromosome Structure • Chromosomes are rod-shaped structures made of DNA and protein. • In eukaryotes, DNA wraps around proteins calledhistonesto help maintain the compact structure of chromosomes.

4. Section 1 Chromosomes Chapter 8 Chromosome Structure

5. Section 1 Chromosomes Chapter 8 Chromosome Structure, continued • Chromosomes in prokaryotes are simpler in structure than chromosomes in eukaryotes.

6. Section 1 Chromosomes Chapter 8 Chromosome Numbers • Each species has a characteristic number of chromosomes in each cell.

7. Section 1 Chromosomes Chapter 8 Chromosome Numbers of Various Organisms

8. 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.

9. 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.

10. 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.

11. Section 2 Cell Division Chapter 8 Cell Division in Prokaryotes • 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.

12. Section 2 Cell Division Chapter 8 Cell Division in Prokaryotes, continued • Binary fissionis the process of cell division in prokaryotes.

13. 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.

14. Section 2 Cell Division Chapter 8 Cell Division in Eukaryotes, continued • Interphase • Interphase consists of growth (G1), DNA replication, and preparation for cell division (G2).

15. 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.

16. Section 2 Cell Division Chapter 8 Stages of Mitosis

17. 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.

18. 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.

19. 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.

20. Section 3 Meiosis Chapter 8 Objectives • Compare the end products of meiosis with those of mitosis. • Summarizethe events of meiosis I. • Explain crossing-over and how it contributes to the production of unique individuals. • Summarizethe events of meiosis II. • Comparespermatogenesis and oogenesis. • Define sexual reproduction.

21. Section 3 Meiosis Chapter 8 Formation of Haploid Cells • Meiosisis 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.

22. Section 3 Meiosis Chapter 8 Formation of Haploid Cells, continued • Meiosisis 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.

23. 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.

24. Section 3 Meiosis Chapter 8 Meiosis II • Meiosis II includes prophase II, metaphase II, anaphase II, and telophase II. • Four new haploid cells result.

25. Section 3 Meiosis Chapter 8 Stages of Meiosis

26. Section 3 Meiosis Chapter 8 Development of Gametes • Spermatogenesisis the process by which sperm cells are produced. • Oogenesisis the process that produces mature egg cells.

27. Section 3 Meiosis Chapter 8 Meiosis in Male and Female Animals

28. Section 3 Meiosis Chapter 8 Sexual Reproduction • Sexual reproductionis 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.