Table of Contents

1
Table of Contents
Cell Reproduction
Chapter 8

• Section 1 Chromosomes
• Section 2 Cell Division
• Section 3 Meiosis

2
Objectives
Section 1 Chromosomes
Chapter 8

• 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.

3
Chromosome Structure
Section 1 Chromosomes
Chapter 8

• 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.

4
Chromosome Structure
Section 1 Chromosomes
Chapter 8
5
Section 1 Chromosomes
Chapter 8
Parts of a Chromosome
Click below to watch the Visual Concept.
Visual Concept
6
Chromosome Structure, continued
Section 1 Chromosomes
Chapter 8

• Chromosomes in prokaryotes are simpler in
  structure than chromosomes in eukaryotes.

7
Chromosome Numbers
Section 1 Chromosomes
Chapter 8

• Each species has a characteristic number of
  chromosomes in each cell.

8
Chromosome Numbers of Various Organisms
Section 1 Chromosomes
Chapter 8
9
Chromosome Numbers, continued
Section 1 Chromosomes
Chapter 8

• 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.

10
Section 1 Chromosomes
Chapter 8
Sex Chromosomes and Autosomes
Click below to watch the Visual Concept.
Visual Concept
11
Chromosome Numbers, continued
Section 1 Chromosomes
Chapter 8

• Diploid and Haploid Cells
• Cells having two sets of chromosomes are diploid
  (2n).
• Haploid cells (1n) have only one set of
  chromosomes.

12
Section 1 Chromosomes
Chapter 8
Karyotype
Click below to watch the Visual Concept.
Visual Concept
13
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.

14
Section 2 Cell Division
Chapter 8
Cell Division in Prokaryotes

• Cell division is the process by which cells
  reproduce themselves.

15
Section 2 Cell Division
Chapter 8
Cell Division in Prokaryotes, continued

• Binary fission is the process of cell division in
  prokaryotes.

16
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.

17
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).

18
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.

19
Stages of Mitosis
Section 2 Cell Division
Chapter 8
20
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.

21
Section 2 Cell Division
Chapter 8
Comparing Cell Division in Plants and Animals
Click below to watch the Visual Concept.
Visual Concept
22
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.

23
Section 2 Cell Division
Chapter 8
Control of the Cell Cycle
Click below to watch the Visual Concept.
Visual Concept
24
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.

25
Section 3 Meiosis
Chapter 8
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.

26
Section 3 Meiosis
Chapter 8
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.

27
Section 3 Meiosis
Chapter 8
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.

28
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.

29
Section 3 Meiosis
Chapter 8
Tetrads and Crossing-over of Genetic Material
Click below to watch the Visual Concept.
Visual Concept
30
Section 3 Meiosis
Chapter 8
Meiosis II

• Meiosis II includes prophase II, metaphase II,
  anaphase II, and telophase II.
• Four new haploid cells result.

31
Stages of Meiosis
Section 3 Meiosis
Chapter 8
32
Section 3 Meiosis
Chapter 8
Comparing Meiosis and Mitosis
Click below to watch the Visual Concept.
Visual Concept
33
Section 3 Meiosis
Chapter 8
Development of Gametes

• Spermatogenesis is the process by which sperm
  cells are produced.
• Oogenesis is the process that produces mature egg
  cells.

34
Meiosis in Male and Female Animals
Section 3 Meiosis
Chapter 8
35
Section 3 Meiosis
Chapter 8
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.

36
Section 3 Meiosis
Chapter 8
Sexual Reproduction
Click below to watch the Visual Concept.
Visual Concept