Biology Seventh Edition Solomon Berg Martin Chapter 9
Biology, Seventh Edition Solomon • Berg • Martin Chapter 9 Chromosomes, Mitosis, and Meiosis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Cells • Basic unit of life • Essential link between generations • Genomes – Even simplest cell contains DNA, collectively called the organism’s genome – Organized into genes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Prokaryotic cells • Circular DNA molecules • Eukaryotic cells • Chromosome packaging facilitated by histones • Histones form nucleosomes • Scaffolding proteins maintain chromosome structure Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Nucleosomes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Mouse metaphase chromosome depleted of histones Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Eukaryotic cell cycle • Beginning of one division to beginning of next • Stages in eukaryotic cell cycle • Interphase – First gap phase – Synthesis phase – Second gap phase • M phase – Mitosis – Cytokinesis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Eukaryotic cell cycle Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Structure of duplicated chromosome • Pair of sister chromatids – Contain identical DNA sequences – Tightly associated in region of centromeres • Each chromatid – Includes region called centromere – Kinetochore attached to each centromere Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Mitosis • Identical chromosomes distributed to each cell pole and a nuclear envelope forms • Stages – Prophase – Metaphase – Anaphase – Telophase Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Stages of Mitosis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Asexual reproduction • Offspring have hereditary traits identical to single parent • Mitosis is basis • Sexual reproduction • Gametes fuse to form a zygote • Meiosis is basis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Diploid cells • Characteristic number of chromosome pairs per cell – Homologous chromosomes – Similar in length, shape, other features, and carry similar attributes • Haploid cells • Contain only one member of each homologous chromosome pair Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Meiosis • Diploid cell undergoing meiosis yields four haploid cells Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Stages of Meiosis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis in the trumpet lily Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Meiotic tetrad with two chiasmata Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Mitosis vs. Meiosis • Mitosis • Meiosis • Prophase • Anaphase • Daughter cells • • • Copyright © 2005 Brooks/Cole — Thomson Learning Prophase I Anaphase I Prophase II Anaphase II Haploid cells
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Mitosis and meiosis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis • Roles of mitosis and meiosis in various life cycles • Many simple eukaryotes remain haploid • In sexual life cycle, meiosis occurs before gametes form • Plants, some algae, and some fungi have complex life cycles with alternation of generations Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 9 Chromosomes, Mitosis, and Meiosis Representative life cycles Copyright © 2005 Brooks/Cole — Thomson Learning
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