Transcript Chapter 8: Cellular Reproduction

Chapter 8
Cell Reproduction
Table of Contents
Section 1 Chromosomes
Section 2 Cell Division
Section 3 Meiosis
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Chapter 8
Section 1 Chromosomes
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.
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Chapter 8
Section 1 Chromosomes
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.
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Chapter 8
Section 1 Chromosomes
Chromosome Structure
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Chapter 8
Section 1 Chromosomes
Parts of a Chromosome
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Chapter 8
Section 1 Chromosomes
Chromosome Structure, continued
• Chromosomes in prokaryotes are simpler in structure
than chromosomes in eukaryotes.
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Chapter 8
Section 1 Chromosomes
Comparing Cell Division in
Prokaryotes and Eukaryotes
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Chapter 8
Section 1 Chromosomes
Chromosome Numbers
• Each species has a characteristic number of
chromosomes in each cell.
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Chapter 8
Section 1 Chromosomes
Chromosome
Numbers of
Various
Organisms
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Chapter 8
Section 1 Chromosomes
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.
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Chapter 8
Section 1 Chromosomes
Sex Chromosomes and Autosomes
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Chapter 8
Section 1 Chromosomes
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.
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Chapter 8
Section 1 Chromosomes
Karyotype
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Chapter 8
Section 2 Cell Division
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.
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Chapter 8
Section 2 Cell Division
Cell Division in Prokaryotes
• Cell division is the process by which cells reproduce
themselves.
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Chapter 8
Section 2 Cell Division
Cell Division in Prokaryotes, continued
• Binary fission is the process of cell division in
prokaryotes.
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Chapter 8
Section 2 Cell Division
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.
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Chapter 8
Section 2 Cell Division
Cell Cycle Introduction
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Chapter 8
Section 2 Cell Division
Cell Division in Eukaryotes, continued
• Interphase
– Interphase consists of growth (G1), DNA
replication, and preparation for cell division (G2).
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Chapter 8
Section 2 Cell Division
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.
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Chapter 8
Section 2 Cell Division
Stages of
Mitosis
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Chapter 8
Section 2 Cell Division
Mitosis
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Chapter 8
Section 2 Cell Division
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.
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Chapter 8
Section 2 Cell Division
Comparing Cell Division in Plants and Animals
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Chapter 8
Section 2 Cell Division
Control of Cell Division
• Cell division in eukaryotes is controlled by many
proteins.
• Control occurs at three main checkpoints.
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Chapter 8
Section 2 Cell Division
Control of the Cell Cycle
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Chapter 8
Section 2 Cell Division
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Chapter 8
Section 2 Cell Division
Control of Cell Division, continued
• When Control is Lost: Cancer
– Cancer may result if cells do not respond to
control mechanisms.
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Chapter 8
Section 3 Meiosis
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.
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Chapter 8
Section 3 Meiosis
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.
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Chapter 8
Section 3 Meiosis
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.
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Chapter 8
Section 3 Meiosis
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.
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Chapter 8
Section 3 Meiosis
Tetrads and Crossing-over of Genetic Material
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Chapter 8
Section 3 Meiosis
Meiosis II
• Meiosis II includes prophase II, metaphase II,
anaphase II, and telophase II.
• Four new haploid cells result.
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Chapter 8
Section 3 Meiosis
Stages of Meiosis
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Chapter 8
Section 3 Meiosis
Stages of Meiosis, continued
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Chapter 8
Section 3 Meiosis
Comparing Meiosis and Mitosis
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Visual Concept
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Chapter 8
Section 3 Meiosis
Development of Gametes
• Spermatogenesis is the process by which sperm
cells are produced.
• Oogenesis is the process that produces mature egg
cells.
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Chapter 8
Section 3 Meiosis
Meiosis in Male and Female Animals
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Chapter 8
Section 3 Meiosis
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.
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Chapter 8
Section 3 Meiosis
Sexual Reproduction
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