Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 9 Chromosomes, Mitosis, and Meiosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 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 EditionCHAPTER 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 EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Nucleosomes
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Mouse metaphase chromosome depleted of histones
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 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 EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Eukaryotic cell cycle
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 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 EditionCHAPTER 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 EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Stages of Mitosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 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 EditionCHAPTER 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 EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Meiosis Diploid cell undergoing meiosis yields four haploid cells
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Stages of Meiosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Meiosis in the trumpet lily
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Meiotic tetrad with two chiasmata
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Mitosis Prophase Anaphase Daughter cells Mitosis vs. Meiosis Meiosis Prophase I Anaphase I Prophase II Anaphase II Haploid cells
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Mitosis and meiosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 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 EditionCHAPTER 9 Chromosomes, Mitosis, and Meiosis Representative life cycles