Unit 1: What is Biology?
Unit 2: Ecology
Unit 3: The Life of a Cell
Unit 4: Genetics
Unit 5: Change Through Time
Unit 6: Viruses, Bacteria, Protists, and Fungi
Unit 7: Plants
Unit 8: Invertebrates
Unit 9: Vertebrates
Unit 10: The Human Body
Unit 1: What is Biology?
Chapter 1: Biology: The Study of Life
Unit 2: Ecology
Chapter 2: Principles of Ecology
Chapter 3: Communities and Biomes
Chapter 4: Population Biology
Chapter 5: Biological Diversity and Conservation
Unit 3: The Life of a Cell
Chapter 6: The Chemistry of Life
Chapter 7: A View of the Cell
Chapter 8: Cellular Transport and the Cell Cycle
Chapter 9: Energy in a Cell
Unit 4: Genetics
Chapter 10: Mendel and Meiosis
Chapter 11: DNA and Genes
Chapter 12: Patterns of Heredity and Human Genetics
Chapter 13: Genetic Technology
Unit 5: Change Through Time
Chapter 14: The History of Life
Chapter 15: The Theory of Evolution
Chapter 16: Primate Evolution
Chapter 17: Organizing Life’s Diversity
Unit 6: Viruses, Bacteria, Protists, and Fungi
Chapter 18: Viruses and Bacteria
Chapter 19: Protists
Chapter 20: Fungi
Unit 7: Plants
Chapter 21:
Chapter 22:
Chapter 23:
Chapter 24:
What Is a Plant?
The Diversity of Plants
Plant Structure and Function
Reproduction in Plants
Unit 8: Invertebrates
Chapter 25: What Is an Animal?
Chapter 26: Sponges, Cnidarians, Flatworms, and
Roundworms
Chapter 27: Mollusks and Segmented Worms
Chapter 28: Arthropods
Chapter 29: Echinoderms and Invertebrate
Chordates
Unit 9: Vertebrates
Chapter 30: Fishes and Amphibians
Chapter 31: Reptiles and Birds
Chapter 32: Mammals
Chapter 33: Animal Behavior
Unit 10: The Human Body
Chapter 34: Protection, Support, and Locomotion
Chapter 35: The Digestive and Endocrine Systems
Chapter 36: The Nervous System
Chapter 37: Respiration, Circulation, and Excretion
Chapter 38: Reproduction and Development
Chapter 39: Immunity from Disease
The Life of a Cell
The Chemistry of Life
A View of the Cell
Cellular Transport and the Cell Cycle
Energy in a Cell
Chapter 8 Cellular Transport and the Cell Cycle
8.1: Cellular Transport
8.1: Section Check
8.2: Cell Growth and Reproduction
8.2: Section Check
8.3: Control of the Cell Cycle
8.3: Section Check
Chapter 8 Summary
Chapter 8 Assessment
What You’ll Learn
You will discover how molecules are
transported across the plasma membrane.
You will sequence the stages of cell division.
You will identify the relationship between
the cell cycle and cancer.
Section Objectives:
• Explain how the processes of diffusion,
passive transport, and active transport occur
and why they are important to cells.
• Predict the effect of a hypotonic, hypertonic,
or isotonic solution on a cell.
Osmosis: Diffusion of Water
• Diffusion is the movement of particles from
an area of higher concentration to an area of
lower concentration.
• In a cell, water always moves to reach an
equal concentration on both sides of the
membrane.
Osmosis: Diffusion of Water
• The diffusion of water across a selectively
permeable membrane is called osmosis.
• Regulating the water flow through the
plasma membrane is an important factor in
maintaining homeostasis within a cell.
What controls osmosis?
• Unequal
distribution
of particles,
called a
concentration
gradient, is
one factor
that controls
osmosis.
Before
Osmosis
Selectively
permeable
membrane
After
Osmosis
Water molecule
Sugar molecule
Cells in an isotonic solution
H2O
H2O
Water Molecule
Dissolved Molecule
• Most cells whether
in multicellular or
unicellular
organisms, are
subject to osmosis
because they are
surrounded by
water solutions.
Cells in an isotonic solution
• In an isotonic
solution, the
concentration of
dissolved substances
in the solution is the
same as the
concentration of
dissolved substances
inside the cell.
H 2O
H2O
Water Molecule
Dissolved Molecule
Cells in an isotonic solution
• In an isotonic
solution, water
molecules move
into and out of
the cell at the
same rate, and
cells retain their
normal shape.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in an isotonic solution
• A plant cell
has its
normal
shape and
pressure in
an isotonic
solution.
Cells in a hypotonic solution
• In a hypotonic
solution, water
enters a cell by
osmosis, causing
the cell to swell.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in a hypotonic solution
• Plant cells swell
beyond their
normal size as
pressure increases.
Cells in a hypertonic solution
• In a hypertonic
solution, water
leaves a cell by
osmosis, causing
the cell to shrink.
H2O
H2O
Water Molecule
Dissolved Molecule
Cells in a hypertonic solution
• Plant cells lose
pressure as the
plasma
membrane
shrinks away
from the cell
wall.
Passive Transport
• When a cell uses no energy to move particles
across a membrane passive transport occurs.
Plasma
membrane
Concentration
gradient
Passive Transport by proteins
• Passive transport of materials across the
membrane using transport proteins is called
facilitated diffusion.
Channel
proteins
Plasma
membrane
Concentration
gradient
Passive Transport by proteins
• Some transport proteins, called channel
proteins, form channels that allow specific
molecules to flow through.
Channel
proteins
Plasma
membrane
Concentration
gradient
Passive transport by proteins
• The movement is with the concentration
gradient, and requires no energy input from
the cell.
Carrier proteins
Concentration
gradient
Plasma
membrane
Step 1
Step 2
Passive transport by proteins
• Carrier proteins change shape to allow a
substance to pass through the plasma
membrane.
Carrier proteins
Concentration
gradient
Plasma
membrane
Step 1
Step 2
Passive transport by proteins
• In facilitated diffusion by carrier protein, the
movement is with the concentration gradient
and requires no energy input from the cell.
Carrier proteins
Concentration
gradient
Plasma
membrane
Step 1
Step 2
Active Transport
• Movement of materials through a membrane
against a concentration gradient is called
active transport and requires energy from the
cell.
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
How active transport occurs
• In active transport, a transport protein called
a carrier protein first binds with a particle of
the substance to be transported.
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
How active transport occurs
Click image to view movie.
How active transport occurs
• Each type of carrier protein has a shape that
fits a specific molecule or ion.
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
How active transport occurs
• When the proper molecule binds with the
protein, chemical energy allows the cell to
change the shape of the carrier protein so
that the particle to be moved is released on
the other side of the membrane.
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
How active transport occurs
• Once the particle is released, the protein’s
original shape is restored.
• Active transport allows particle movement
into or out of a cell against a concentration
gradient.
Carrier
proteins
Plasma
membrane
Concentration
gradient
Cellular
energy
Step 1
Step 2
How active transport occurs
Click image to view movie.
Transport of Large Particles
• Endocytosis is a process by which a cell
surrounds and takes in material from its
environment.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• The material is engulfed and enclosed by a
portion of the cell’s plasma membrane.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• The resulting vacuole with its contents
moves to the inside of the cell.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• Exocytosis is the expulsion or secretion of
materials from a cell.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Transport of Large Particles
• Endocytosis and exocytosis both move
masses of material and both require energy.
Nucleus
Wastes
Digestion
Endocytosis
Exocytosis
Question 1
The diffusion of
water across a
selectively
permeable
membrane is
called
__________.
(TX Obj 2; 4B)
A. active transport
Selectively
permeable
membrane
Water molecule
Sugar molecule
B. endocytosis
Question 1
The diffusion of
water across a
selectively
permeable
membrane is
called
__________.
(TX Obj 2; 4B)
C. exocytosis
Selectively
permeable
membrane
D. osmosis
Water molecule
Sugar molecule
The answer is D,
osmosis.
Regulating the
water flow
through the
plasma
membrane is an
important factor
in maintaining
homeostasis
within the cell.
Before osmosis
Selectively
permeable
membrane
After osmosis
Water molecule
Sugar molecule
Question 2
What is the expected result of having an animal
cell in a hypertonic solution? (TX Obj 2; 4B)
A. The cell shrivels up.
B. The plasma membrane shrinks away from
the cell wall.
C. The cell swells up.
D. The cell retains its normal shape.
The answer is A. In a hypertonic solution, cells
experience osmosis of water out of the cell.
Animal cells shrivel because of decreased
pressure in the cells.
H2O
H2O
Water molecule
Sugar molecule
Question 3
A grocer mists the celery display with water to
keep it looking fresh. What type of solution is
the celery now in? (TX Obj 2; 4B)
A. isotonic
B. hypotonic
C. hypertonic
D. exotonic
The answer is B. Plant cells contain a rigid cell
wall and do not burst even in a hypotonic
solution.
Question 4
Transport of materials across the plasma
membrane that does not require energy from the
cell but does use transport proteins is called
__________.
Channel
(TX Obj 2; 4B)
proteins
A. osmosis
B. simple
diffusion
Plasma
membrane
Concentration
gradient
Question 4
Transport of materials across the plasma
membrane that does not require energy from the
cell but does use transport proteins is called
__________.
Channel
(TX Obj 2; 4B)
proteins
C. facilitated
diffusion
D. active
transport
Plasma
membrane
Concentration
gradient
The answer is C. Facilitated diffusion is a type
of passive transport and requires no energy
from the cell.
Channel
proteins
Plasma
membrane
Concentration
gradient
Section Objectives
• Sequence the events of the cell cycle.
• Relate the function of a cell to its
organization in tissues, organs, and organ
systems.
Cell Size Limitations
• The cells that make up a multicellular
organism come in a wide variety of sizes and
shapes.
• Considering this wide range of cells sizes,
why then can’t most organisms be just one
giant cell?
Diffusion limits cell size
• Although diffusion is a fast and efficient
process over short distances, it becomes slow
and inefficient as the distances become
larger.
• Because of the slow rate of diffusion,
organisms can’t be just one giant-sized cell.
DNA limits cell size
• The cell cannot survive unless there is
enough DNA to support the protein needs
of the cell.
• In many large cells, more than one nucleus
is present.
• Large amounts of DNA in many nuclei
ensure that cell activities are carried out
quickly and efficiently.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 8 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• As a cell’s size increases, its volume
increases much faster than its surface area.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 8 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• If cell size doubled, the cell would require
eight times more nutrients and would have
eight times more waste to excrete.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 8 mm3
4 mm
2 mm
2 mm
4 mm
Surface area = 24 mm2
Volume = 8 mm3
• The surface area, however, would increase
by a factor of only four.
Surface area-to-volume ratio
4 mm
1 mm
2 mm
1 mm
1 mm
mm2
Surface area = 6
Volume = 8 mm3
4 mm
2 mm
2 mm
Surface area = 24 mm2
Volume = 8 mm3
• The cell would either starve to death or be
poisoned from the buildup of waste
products.
4 mm
Cell Reproduction
• Cell division is the process by which new
cells are produced from one cell.
• Cell division results in two cells that are
identical to the original, parent cell.
The discovery of chromosomes
• Structures, which contain DNA and become
darkly colored when stained, are called
chromosomes.
• Chromosomes are the carriers of the genetic
material that is copied and passed from
generation to generation of cells.
• Accurate transmission of chromosomes
during cell division is critical.
The structure of eukaryotic chromosomes
Centromere
Sister
chromatids
Supercoil within
chromosome
Chromosome
Continued coiling
within supercoil
Histone H1
Nucleosome
DNA
The Cell Cycle
• The cell cycle is the sequence of growth and
division of a cell.
• The majority of a
cell’s life is spent
in the growth
period known as
interphase.
Interphase
The Cell Cycle
• Following interphase, a cell enters its period
of nuclear division called mitosis.
• Following
mitosis, the
cytoplasm
divides,
separating the
two daughter
Mitosis
cells.
Interphase: A Busy Time
• Interphase, the busiest phase of the cell
cycle, is divided into three parts.
Interphase
DNA synthesis
and replication
Rapid
growth
and
metabolic
activity
Centrioles replicate;
cell prepares for
division
Interphase: A Busy Time
• During the first part, the cell grows and
protein production is high.
Interphase
Rapid
growth
and
metabolic
activity
Interphase: A Busy Time
• In the next part of interphase, the cell copies
its chromosomes.
Interphase
DNA synthesis
and replication
Interphase: A Busy Time
• After the chromosomes have been
duplicated, the cell enters another shorter
growth period in which mitochondria and
other organelles are manufactured and cell
parts needed for cell division are assembled.
Interphase
Centrioles replicate; cell
prepares for division
The Phases of Mitosis
• The four phases of mitosis are prophase,
metaphase, anaphase, and telophase.
Prophase: The first phase of mitosis
• During prophase, the chromatin coils to form
visible chromosomes.
Spindle fibers
Disappearing
nuclear envelope
Doubled
chromosome
Prophase: The first phase of mitosis
• The two halves of the doubled structure are
called sister chromatids.
Sister
chromatids
Prophase: The first phase of mitosis
• Sister chromatids are held together by a
structure called a centromere, which plays
a role in chromosome movement during
mitosis.
Centromere
Metaphase: The second stage of mitosis
• During metaphase, the chromosomes move
to the equator of the spindle.
Centromere
Sister
chromatids
Anaphase: The third phase of mitosis
• During anaphase, the centromeres split and
the sister chromatids are pulled apart to
opposite poles of the cell.
Telophase: The fourth phase of mitosis
• During telophase, two distinct daughter cells
are formed. The cells separate as the cell
cycle proceeds into the next interphase.
Nuclear
envelope
reappears
Two daughter cells are formed
Cytokinesis
• Following telophase, the cell’s cytoplasm
divides in a process called cytokinesis.
• Cytokinesis differs between plants and
animals.
• Toward the end of telophase in animal cells,
the plasma membrane pinches in along the
equator.
Cytokinesis
• Plant cells have a rigid cell wall, so the
plasma membrane does not pinch in.
• A structure known as the cell plate is laid
down across the cell’s equator.
• A cell membrane forms around each cell, and
new cell walls form on each side of the cell
plate until separation is complete.
Results of Mitosis
• When mitosis is complete, unicellular
organisms remain as single cells.
• In multicellular organisms, cell growth and
reproduction result in groups of cells that
work together as tissue to perform a specific
function.
Results of Mitosis
• Tissues organize in various combinations to
form organs that perform more complex
roles within the organism.
• Multiple organs that work together form an
organ system.
Results of Mitosis
Click image to view movie.
Question 1
The stringy structures in the cell nucleus that
contain DNA are __________. (TX Obj 2;
4B)
A. centromeres
B. chromosomes
C. genes
D. chlorophylls
The answer is B. Chromosomes are the carriers
of the genetic material of the cell. A gene is a
segment of DNA that controls the production of
a protein.
Question 2
Look at the diagram and identify the stage of
mitosis that is depicted. (TX Obj 2; 4B)
Centromere
Sister
chromatids
A. prophase
C. anaphase
B. metaphase
D. telophase
The answer is B. Metaphase is the short second
phase of mitosis, during which the
chromosomes begin to line up on the equator of
the spindle.
Centromere
Sister
chromatids
Question 3
What is the process by which a cell's cytoplasm
divides? (TX Obj 2; 4B)
A. cytokinesis
B. telekinesis
C. meiosis
D. mitosis
The answer is A. Cytokinesis follows telophase
and allows the two new cells to separate.
Question 4
In multicellular organisms, groups of cells that
work together to perform a specific function
are called __________. (TX Obj 2; 10B)
A. organ systems
B. organs
C. tissues
D. cell cycles
The answer is C. Tissues organize to form
organs, which work with other organs to form
organ systems.
Section Objectives
• Describe the role of enzymes in the
regulation of the cell cycle.
• Distinguish between the events of a normal
cell cycle and the abnormal events that
result in cancer.
• Identify ways to potentially reduce the risk
of cancer.
Normal Control of the Cell Cycle
Proteins and enzymes control the
cell cycle
• The cell cycle is controlled by proteins called
cyclins and a set of enzymes that attach to
the cyclin and become activated.
• Occasionally, cells lose control of the cell
cycle.
Normal Control of the Cell Cycle
• This uncontrolled dividing of cells can result
from the failure to produce certain enzymes,
the overproduction of enzymes, or the
production of other enzymes at the wrong
time.
• Cancer is a malignant growth resulting from
uncontrolled cell division.
Normal Control of the Cell Cycle
• Enzyme production is directed by genes
located on the chromosomes.
• A gene is a segment of DNA that
controls the production of a protein.
Cancer: A mistake in the Cell Cycle
• Currently, scientists consider cancer to be a
result of changes in one or more of the genes
that produce substances that are involved in
controlling the cell cycle.
• Cancerous cells form masses of tissue called
tumors that deprive normal cells of nutrients.
Cancer: A mistake in the Cell Cycle
• In later stages, cancer cells enter the
circulatory system and spread throughout the
body, a process called metastasis, forming
new tumors that disrupt the function of
organs, organ systems, and ultimately, the
organism.
The causes of cancer
• The causes of cancer are difficult to pinpoint
because both genetic and environmental
factors are involved.
The causes of cancer
• Environmental
factors, such as
cigarette smoke, air
and water pollution,
and exposure to
ultraviolet radiation
from the sun, are all
known to damage the
genes that control the
cell cycle.
The causes of cancer
• Cancer may also be caused by viral
infections that damage the genes.
Cancer prevention
• Physicians and dietary experts agree that diets
low in fat and high in fiber content can reduce
the risk of many kinds of cancer.
• Vitamins and minerals may also help prevent
cancer.
Cancer prevention
• In addition to
diet, other healthy
choices such as
daily exercise and
not using tobacco
also are known to
reduce the risk of
cancer.
Question 1
Explain cancer in terms of cell growth.
(TX Obj 2; 4B, 6C)
Answer
Cancer is a malignant growth resulting from
uncontrolled cell division. The loss of control
may be caused by environmental factors or
changes in enzyme production that result from
defective or changed genetic material.
Cancerous cells form masses of tissue called
tumors that deprive normal cells of nutrients.
Question 2
A(n) __________ is a segment of DNA
that controls the production of a protein.
(TX Obj 2; 4B, 6C)
A. gene
B. cyclin
C. enzyme
D. chromosome
The answer is A. Genes control the production
of proteins. Scientists think that cancer results
from changes in one or more of the genes that
produce substances controlling the cell cycle.
Question 3
Which of the following is thought to reduce the
risk of developing cancer? (TX Obj 2; 4B)
A. increase dietary fat
B. increase dietary fiber
C. decrease dietary fiber
D. decrease dietary minerals
The answer is B. Health professionals believe
that diets low in fat and high in fiber content
can reduce the risk of many types of cancer.
Cellular Transport
• Osmosis is the diffusion of water through a
selectively permeable membrane.
• Passive transport moves a substance with the
concentration gradient and requires no energy
from the cell.
Cellular Transport
• Active transport moves materials against the
concentration gradient and requires energy to
overcome the flow of materials opposite the
concentration gradient.
• Large particles may enter a cell by endocytosis
and leave by exocytosis.
Cell Growth and Reproduction
• Cell size is limited largely by the diffusion rate of
materials into and out of the cell, the amount of
DNA available to program the cell’s metabolism,
and the cell’s surface area-to-volume ratio.
• The life cycle of a cell is divided into two
general periods: a period of active growth and
metabolism known as interphase, and a period
that leads to cell division known as mitosis.
Cell Growth and Reproduction
• Mitosis is divided into four phases: prophase,
metaphase, anaphase, and telophase.
• The cells of most multicellular organisms are
organized into tissues, organs, and organ
systems.
Control of the Cell Cycle
• The cell cycle is controlled by key enzymes
that are produced at specific points in the cell
cycle.
• Cancer is caused by genetic and
environmental factors that change the
genes that control the cell cycle.
Question 1
Which of the following is a factor that controls
osmosis? (TX Obj 2; 4B)
A. prophase
B. concentration gradient
C. conditioning
D. carrier proteins
The answer is B. Osmosis is the diffusion of
water across a selectively permeable membrane.
Concentration gradients, unequal distributions
of particles, result in water diffusing to the side
of the membrane where the water concentration
is lower.
Question 2
Predict the result of placing a fresh stalk of
celery in a jar of salt water. (TX Obj 2; 4B)
Answer
Salt water would be a hypertonic solution for the
celery. Water will leave the cells by osmosis. As
a result, the cells will lose pressure as the
plasma membrane shrinks away from the cell
wall and the celery will probably wilt.
Question 3
Magnification of a plant cell reveals centromeres
that have split and sister chromatids being pulled
to opposite poles of the cell. This cell is in which
phase of mitosis? (TX Obj 2; 4B)
A. prophase
B. metaphase
C. anaphase
D. telophase
The answer is C. The separation of sister
chromatids marks the beginning of anaphase,
and the final phase, telophase, begins as the
chromatids reach the opposite poles of the cell.
Question 4
Which phase of mitosis is depicted in this
diagram? (TX Obj 2; 4B)
Spindle Fibers
Doubled
chromosome
Disappearing
nuclear envelope
A. prophase
C. anaphase
B. metaphase
D. telophase
The answer is A. Prophase is the first and
longest phase of mitosis, during which the long,
stringy chromatin coils up into visible
chromosomes. Sister chromatids have formed,
but are not yet lined up along the equator of the
spindle.
Spindle Fibers
Doubled
chromosome
Disappearing
nuclear envelope
Question 5
What is the term used for the period of the cell
cycle represented by the red arrow in this graph?
(TX Obj 2; 4B)
A. prophase
B. metaphase
C. centrophase
DNA synthesis
and replication
Centrioles
replicate; cell
prepares for
division
Rapid growth
and metabolic
activity
Mitosis
D. interphase
Cytokinesis
The answer is D. Most of the time spent in
the cell cycle is in interphase.
Interphase
Question 6
The structure depicted in this diagram forms
during prophase of mitosis. During metaphase,
doubled chromosomes will become attached to
this by their centromeres. What is this structure?
(TX Obj 2; 4B)
A. spindle
B. centriole
C. chromatid
D. chromatin
Microtubule
The answer is A. This cage like structure is a
spindle, consisting of thin fibers made of
microtubules. The chromosomes will become
attached to the spindle fibers by their
centromeres, and will be pulled to the midline
of the spindle.
Microtubule
Question 7
What is the level of organization that is missing
in this diagram? (TX Obj 2; 4B)
Cell
(muscle cell)
?
Organ
(stomach)
Organ System
(digestive tissue)
A. mass
C. tissue
B. cluster
D. cycle
Organism
(Florida Panther)
The answer is C. In multicellular organisms,
groups of cells that work together are tissues.
Tissues are formed from different types of cells
that are coded for by different parts of the
original cell's genetic material.
Tissue
Cell
(muscle cell) (muscle tissue)
Organ
(stomach)
Organ System
(digestive tissue)
Organism
(Florida Panther)
Question 8
Which structure represents a cell in prophase of
mitosis? (TX Obj 2; 4B)
A
B
C
A. A
C. C
B. B
D. D
D
The answer is C. The chromosomes have
doubled but are still contained within the
nucleus.
C
Photo Credits
• Digital Stock
• KS Studios/Bob Mullenix
• Alton Biggs
To advance to the next item or next page click on any of the
following keys: mouse, space bar, enter, down or forward
arrow.
Click on this icon to return to the table of contents
Click on this icon to return to the previous slide
Click on this icon to move to the next slide
Click on this icon to open the resources file.
End of Chapter 8 Show