Think Critically

  1. Predict The beaker in the diagram below has a selectively permeable membrane separating two solutions. Assume that both water and salt can pass freely through the membrane. When equilibrium is reached, will the fluid levels be the same as they are now? Explain.

    An illustration shows a beaker which is divided into two compartments A and B by a selectively permeable membrane. Side A has concentrated salt solution and side B has dilute salt and starch solution.

  2. Predict What would happen to a sample of your red blood cells if they were placed in a hypotonic solution? Explain.

  3. Design Experiments You are given food coloring and three beakers. The first beaker contains water at room temperature, the second beaker contains ice water, and the third beaker contains hot water. Design a controlled experiment to determine the effects of temperature on the rate of diffusion. Be sure to state your hypothesis.

7.4 Homeostasis and Cells

Understand Key Concepts

  1. Which of the following is true of ALL single-celled organisms?

    1. They are all prokaryotes.

    2. They are all bacteria.

    3. They all reproduce.

    4. They all have a nucleus.

  2. A tissue is composed of a group of

    1. similar cells.

    2. related organelles.

    3. organ systems.

    4. related organs.

  3. Explain the relationship among cell specialization, multicellular organisms, and homeostasis.

  4. Describe the relationship among cells, tissues, organs, and organ systems.

solve the CHAPTER MYSTERY

A photograph of a runner suffering from hypernatremia due to excess salt depletion.

DEATH BY… WATER?

During the race, Michelle drank plenty of water, but she didn't replace the salts she lost due to sweating. As a result, her blood became hypotonic, and osmotic pressure led the cells in her brain (and throughout her body) to swell.

As Michelle's blood became more dilute, cells in her brain sent chemical signals to her kidneys to stop removing sodium chloride and other salts from her bloodstream. However, as she continued to sweat, she continued to lose salt through her skin.

By the end of the race, Michelle had lost a large quantity of salt and minerals and had taken in so much water that homeostasis had broken down, and her cells were damaged by unregulated osmotic pressure.

When Michelle was rushed to the hospital, the doctors discovered that she was suffering from hyponatremia, or water intoxication. Left untreated, this condition can lead to death.

  1. Relate Cause and Effect When a person sweats, water and essential solutes called electrolytes are lost from body fluid. Michelle drank lots of water but did not replace lost electrolytes. What effect did this have on her cells?

  2. Infer Had Michelle alternated between drinking water and a sports drink with electrolytes would her condition be the same?

  3. Infer Do you think that hyponatremia results from osmosis or active transport? Explain your reasoning.

  4. Connect to the Explain how hyponatremia disrupts homeostasis in the body.

End ofPage 221

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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