Transcript The Body in Motion

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
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Nucleosomes
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Mouse metaphase
chromosome
depleted of histones
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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
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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
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Stages
of
Mitosis
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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
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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
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Meiosis in the trumpet lily
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Meiotic tetrad with two chiasmata
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Mitosis vs. Meiosis
•Mitosis
•Meiosis
• Prophase
• Anaphase
• Daughter cells
•
•
•
•
•
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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
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Biology, Seventh Edition
CHAPTER 9 Chromosomes, Mitosis, and Meiosis
Representative
life cycles
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