Anaphase The third phase of mitosis, anaphase, begins when sister chromatids suddenly separate and begin to move apart. Once anaphase begins, each sister chromatid is now considered an individual chromosome. During anaphase, the chromosomes separate and move along spindle fibers to opposite ends of the cell. Anaphase comes to an end when this movement stops and the chromosomes are completely separated into two groups.

Telophase Following anaphase is telophase, the fourth and final phase of mitosis. During telophase, the chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin. A nuclear envelope re-forms around each cluster of chromosomes. The spindle begins to break apart, and a nucleolus becomes visible in each daughter nucleus. Mitosis is complete. However, the process of cell division has one more step to go.

In Your Notebook Create a chart that lists the important information about each phase of mitosis.

An illustration shows anaphase stage of cell division where the chromosomes separate and move along spindle fibers to opposite ends of the cell.

FIGURE 10–10 Anaphase

An illustration shows telophase stage of cell division where chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin. The nuclear envelope reforms again.

FIGURE 10–11 Telophase

Quick Lab
GUIDED INQUIRY

Mitosis in Action

  1. Examine a slide of a stained onion root tip under a microscope. Viewing the slide under low power, adjust the stage until you find the boxlike cells just above the root tip.

  1. Switch the microscope to high power and locate cells that are in the process of dividing.

  1. Find and sketch cells that are in each phase of mitosis. Label each sketch with the name of the appropriate phase.

    Analyze and Conclude

  1. Observe In which phase of the cell cycle were most of the cells you observed? Why do you think this is?

  2. Draw Conclusions What evidence did you observe that shows mitosis is a continuous process, not a series of separate events?

  3. Apply Concepts Cells in the root divide many times as the root grows longer and thicker. With each cell division, the chromosomes are divided between two daughter cells, yet the number of chromosomes in each cell does not change. What processes ensure that the normal number of chromosomes is restored after each cell division?

A slide of a stained onion root tip viewed under a light microscope showing cells with different stages of cell division.

End ofPage 283

Table of Contents

Miller & Levine Biology
About the Authors
Changing the World of Biology Education
Contents
Diversity of Life: A Visual Guide DOL•1–DOL•64
Labs and Activities
Features
UNIT 1 The Nature of Life
1 The Science of Biology
2 The Chemistry of Life
Unit Project
UNIT 2 Ecology
3 The Biosphere
4 Ecosystems and Communities
5 Populations
6 Humans in the Biosphere
Unit Project
UNIT 3 Cells
7 Cell Structure and Function
8 Photosynthesis
9 Cellular Respiration and Fermentation
10 Cell Growth and Division
Unit Project
UNIT 4 Genetics
11 Introduction to Genetics
12 DNA
13 RNA and Protein Synthesis
14 Human Heredity
15 Genetic Engineering
Unit Project
UNIT 5 Evolution
16 Darwin's Theory of Evolution
17 Evolution of Populations
18 Classification
19 History of Life
Unit Project
UNIT 6 From Microorganisms to Plants
20 Viruses and Prokaryotes
21 Protists and Fungi
22 Introduction to Plants
23 Plant Structure and Function
24 Plant Reproduction and Response
Unit Project
UNIT 7 Animals
25 Introduction to Animals
26 Animal Evolution and Diversity
27 Animal Systems I
28 Animal Systems II
29 Animal Behavior
Unit Project
UNIT 8 The Human Body
30 Digestive and Excretory Systems
31 Nervous System
32 Skeletal, Muscular, and Integumentary Systems
33 Circulatory and Respiratory Systems
34 Endocrine and Reproductive Systems
35 Immune System and Disease
Unit Project
A Visual Guide to The Diversity of Life
HOW TO USE THIS GUIDE
THE TREE OF LIFE
Bacteria
Protists
Fungi
Plants
Animals
Appendices
Appendix A Science Skills
Appendix B Lab Skills
Appendix C Technology & Design
Appendix D Math Skills
Appendix E Periodic Table
Glossary
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q, R
S
T
U
V
W
X, Y, Z
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Credits
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