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 7 A View of a Cell
7.1: The Discovery of Cells
7.1: Section Check
7.2: The Plasma Membrane
7.2: Section Check
7.3: Eukaryotic Cell Structure
7.3: Section Check
Chapter 7 Summary
Chapter 7 Assessment
What You’ll Learn
You will identify the parts of prokaryotic
and eukaryotic cells.
You will identify the structure and
function of the plasma membrane.
You will relate the structure of cell
parts to their functions.
What You’ll Learn
Cells are the foundation for the
development of all life forms. Birth,
growth, death, and all life functions
begin as cellular functions.
Lysosomes
Nucleus
Plasma
Membrane
Endoplasmic
Reticulum
Mitochondrion
Section Objectives:
• Relate advances in microscope technology to
discoveries about cells and cell structure.
• Compare the operation of a microscope with
that of an electron microscope.
• Identify the main ideas of the cell theory.
The History of the Cell Theory
• Before microscopes were invented, people
believed that diseases were caused by curses
and supernatural spirits.
• As scientists began using microscopes, they
quickly realized they were entering a new
world–one of microorganisms.
• Microscopes enabled scientists to view
and study cells, the basic units of living
organisms.
Development of Light Microscopes
• The first person to record looking at water
under a microscope was Anton van
Leeuwenhoek.
• The microscope van Leeuwenhoek used is
considered a simple light microscope
because it contained one lens and used
natural light to view objects.
Development of Light Microscopes
Compound light microscopes use a series of
lenses to magnify objects in steps.
These
microscopes
can magnify
objects up to
1 500 times.
Microscope Lab Techniques
Click image to view movie.
The Cell Theory
• Robert Hooke was an English scientist who
lived at the same time as van Leeuwenhock.
• Hooke used a compound light microscope to
study cork, the dead cells of oak bark.
Cells are the basic building blocks of
all living things.
The cell theory is made up of three main
ideas:
All organisms are composed of one or
more cells.
The cell is the basic unit of
organization of organisms.
All cells come from preexisting
cells.
Development of Electron Microscopes
• The electron microscope was invented in the 1940s.
• This microscope
uses a beam of
electrons to
magnify
structures up to
500 000 times
their actual size.
Development of Electron Microscopes
There are two basic types of electron microscopes.
The scanning electron microscope scans the
surface of cells to learn their three dimensional
shape.
The transmission electron microscope allows
scientists to study the structures contained
within a cell.
Two Basic Cell Types
Cells that do not contain internal
membrane-bound structures are called
prokaryotic cells.
Click here
• The cells of most unicellular organisms
such as bacteria do not have membrane
bound structures and are therefore called
prokaryotes.
7.1
Two Basic Cell Types
Cells containing membrane-bound structures
are called eukaryotic cells.
Click here
• Most of the multi-cellular plants and
animals we know are made up of cells
containing membrane-bound structures and
are therefore called eukaryotes.
Two Basic Cell Types
The membrane-bound structures within
eukaryotic cells are called organelles.
• Each organelle has a specific function that
contributes to cell survival.
Two Basic Cell Types
• Separation of organelles into distinct
compartments benefits the eukaryotic
cells.
The nucleus is the central membranebound organelle that manages cellular
functions.
Question 1
How did the invention of the microscope
impact society's understanding of disease?
A. Scientists were able to view microorganisms
that were previously unknown.
B. Microscopes were invented after the
development of the cell theory.
CA: Biology/Life Sciences
10a-10f
Question 1
How did the invention of the microscope impact
society's understanding of disease?
C. It was once believed that viruses, not
bacteria, caused diseases.
D. Scientists could view membrane-bound
organelles of prokaryotes.
CA: Biology/Life Sciences
10a-10f
The answer is A. Before microscopes were
invented, people believed that curses and
supernatural spirits caused diseases.
Microscopes enabled scientists to view cells,
which led to the discovery that microorganisms
cause some diseases.
CA: Biology/Life Sciences
10a-10f
Question 2
Which of the following uses a beam of light
and a series of lenses to magnify objects in
steps?
A. compound light microscope
B. scanning electron microscope
C. transmission electron microscope
D. simple light microscope
CA: Inv. & Exp. 1a
The answer is A. Most microscopes use at least
two convex lenses. Compound light microscopes
use a light beam and a series of lenses and can
magnify objects up to about 1500 times. Electron
microscopes use a beam of electrons and can
magnify structures up to 500 000 times.
CA: Inv. & Exp. 1a
Question 3
What makes this cell eukaryotic?
A. Because it
has a cell wall.
B. Because it
contains DNA.
CA: Biology/Life Sciences
1c, 1j
Nucleus
Nucleolus
Chromosomes
Plasma
membrane
Organelles
Question 3
What makes this cell eukaryotic?
C. Because it
Nucleus
has membrane- Nucleolus
bound
Chromosomes
organelles.
D. Because it
does not have
DNA.
CA: Biology/Life Sciences
1c, 1j
Plasma
membrane
Organelles
Question 3
The Answer is C. Eukaryotic cells contain
membrane-bound organelles that have specific
functions in the cell; prokaryotic cells do not.
Nucleus
Nucleolus
Chromosomes
Plasma
membrane
CA: Biology/Life Sciences
1c, 1j
Organelles
Section Objectives
• Explain how a cell’s plasma membrane
functions.
• Relate the function of the plasma membrane
to the fluid mosaic model.
All living cells must maintain a balance
regardless of internal and external conditions.
Survival depends on the cell’s ability to
maintain the proper conditions within itself.
Why cells must control materials
The plasma
membrane is the
boundary
between the cell
and its
environment.
It is the plasma membrane’s job to:
• allow a steady supply of glucose, amino acids,
and lipids to come into the cell no matter what
the external conditions are.
• remove excess amounts of these nutrients when
levels get so high that they are harmful.
• allow waste and other products to leave the
cell.
This process of maintaining the cell’s
environment is called homeostasis.
Selective permeability is a process used to
maintain homeostasis in which the plasma
membrane allows some molecules into the
cell while keeping others out.
Plasma
Membrane
Water
Structure of the Plasma Membrane
The plasma
membrane is
composed of two
layers of
phospholipids
back-to-back.
Phospholipids are lipids with a
phosphate attached to them.
The lipids in a
plasma membrane
have a glycerol
backbone, two
fatty acid chains,
and a phosphate
group.
Phosphate
Group
Glycerol
Backbone
Two Fatty
Acid
Chains
Makeup of the phospholipid bilayer
The phosphate
group is critical
for the formation
and function of
the plasma
membrane.
Phosphate
Group
Makeup of the phospholipid bilayer
The fluid mosaic model describes the plasma
membrane as a flexible boundary of a cell. The
phospholipids move within the membrane.
Other components of the plasma
membrane:
Cholesterol plays the important role of
preventing the fatty acid chains of the
phospholipids from sticking together.
Cholesterol
Molecule
Other components of the plasma
membrane:
Transport proteins
allow needed
substances or waste
materials to move
through the plasma
membrane.
Click image to view movie.
Question 1
Which of the following best describes the
plasma membrane's mechanism in maintaining
homeostasis?
A. protein synthesis
B. selective permeability
C. fluid composition
D. structural protein attachment
CA: Biology/Life Sciences
1a
The answer is B. Selective permeability is the
process in which the membrane allows some
molecules to pass through, while keeping others
out.
CA: Biology/Life Sciences
1a
Question 2
Describe the
structure of the
plasma membrane.
CA: Biology/Life Sciences
1a
The plasma membrane is composed of a
phospholipid bilayer, which has two layers of
phospholipids back-to-back. The polar heads of
phospholipid molecules contain phosphate
groups and face outward.
CA: Biology/Life Sciences
1a
Question 3
Why is the
phosphate
group of a
phospholipid
important to
the plasma
membrane?
CA: Biology/Life Sciences
1a
Phospholipid molecule
Nonpolar
tails (fatty
acids)
Polar head
(includes
phosphate
group)
When phospholipid
Phospholipid molecule
molecules form a
bilayer, the phosphate
Polar head
groups lie to the
(includes
outside. Because
phosphate
Nonpolar
phosphate groups are tails (fatty
group)
polar, they allow the acids)
cell membrane to
interact with its
watery (polar)
environments inside
and outside the cell.
CA: Biology/Life Sciences
1a
Question 4
Explain why the model of the plasma
membrane is called the fluid mosaic model.
CA: Biology/Life Sciences
1a
It is fluid because the phospholipid molecules
move within the membrane. Proteins in the
membrane that move among the phospholipids
create the mosaic pattern.
CA: Biology/Life Sciences
1a
Section Objectives
• Understand the structure and function of the
parts of a typical eukaryotic cell.
• Explain the advantages of highly folded
membranes.
• Compare and contrast the structures of plant
and animal cells.
Cellular Boundaries
The plasma
membrane acts as
a selectively
permeable
membrane.
The cell wall
The cell wall is a
fairly rigid structure
located outside the
plasma membrane
that provides
additional support
and protection.
Nucleus and cell control
Nucleolus
Chromatin
Nuclear
Envelope
Assembly, Transport, and Storage
The endoplasmic
reticulum (ER) is an
organelle that is
suspended in the
cytoplasm and is the
site of cellular
chemical reactions.
Assembly, Transport, and Storage
Endoplasmic
Reticulum (ER)
Ribosomes
Assembly, Transport, and Storage
Golgi
Apparatus
Vacuoles and storage
Vacuoles are membrane-bound spaces used for
temporary storage of materials. Notice the
difference between vacuoles in plant and animal
cells.
Animal
Cell
Vacuole
Plant
Cell
Lysosomes and recycling
Lysosomes are organelles that contain
digestive enzymes. They digest excess or
worn out organelles, food particles, and
engulfed viruses or bacteria.
Energy Transformers:
Chloroplasts and energy
Chloroplasts are
cell organelles that
capture light energy
and produce food
to store for a later
time.
Chloroplasts and energy
The chloroplasts belongs to a group of plant
organelles called plastids, which are used for
storage.
Chloroplasts contain green pigment called
chlorophyll. Chlorophyll traps light energy
and gives leaves and stems their green color.
Mitochondria and energy
Mitochondria are
membrane-bound
organelles in plant
and animal cells that
transform energy for
the cell.
Mitochondria and energy
A mitochondria, like the
endoplasmic reticulum,
has a highly folded
inner membrane.
Energy storing
molecules are produced
on inner folds.
Structures for Support and Locomotion
Cells have a support structure called the
cytoskeleton within the cytoplasm. The
cytoskeleton is composed of microtubules
and microfilaments. Microtubules are thin,
hollow cylinders made of protein and
microfilaments are thin solid protein fibers.
Cilia and flagella
Some cell surfaces have cilia and flagella,
which are structures that aid in locomotion
or feeding. Cilia and flagella can be
distinguished by their structure and by the
nature of their action.
Cilia and flagella
Cilia are short,
numerous, hair-like
projections that
move in a wavelike
motion.
Cilia
Cilia and flagella
Flagella
Flagella are long
projections that move
in a whip-like motion.
Flagella and cilia are
the major means of
locomotion in
unicellular organisms.
Question 1
What is the primary function of the cell wall?
A. act as selectively permeable membrane
B. provide support
C. control activity of organelles
D. acquire nutrients from environment
CA: Cell Bio 1c, 1j
The answer is B. The
cell wall is an
inflexible, porous
barrier that provides
support but does not
select which
molecules can enter
the cell.
CA: Cell Bio 1c, 1j
Question 2
Describe the
control center of
a prokaryotic
cell.
CA: Cell Bio 1c
Ribosomes
DNA
Plasma
membrane
Cell wall
Prokaryotic cells do not have true nuclei; their
DNA is not separated from the rest of the cell
by a membrane.
Plasma
Ribosomes
DNA
membrane
Cell wall
CA: Cell Bio 1c
Question 3
Which of the following structures is the site of
protein synthesis?
A. Golgi apparatus
B. Ribosome
C. Vacuole
D. Lysosome
CA: Cell Bio 1d
The answer is B. Ribosomes are the sites
where the cell produces proteins according to
the directions of DNA. They can be attached to
the surface of the endoplasmic reticulum or
float freely in the cytoplasm.
CA: Cell Bio 1d
Question 4
What is the advantage of having numerous folds
in the ER?
A. It enables the ER to lie snugly against the
nucleolus.
B. It can create more vesicles in a smaller
space.
CA: Cell Bio 1e
Question 4
What is the advantage of having numerous folds
in the ER?
C. It can capture more light energy with more
folds.
D. A large amount of work can be done in a
small space.
CA: Cell Bio 1e
The answer is D.
The ER is
arranged in a
series of folded
membranes,
which, if spread
out, would take
up tremendous
space.
CA: Cell Bio 1e
Question 5
What could you predict about a plant cell that
contains fewer chloroplasts than other plant
cells?
A. It contains less chlorophyll.
B. It contains a greater number of plastids.
C. It will have an increased rate of light
energy capture.
D. It will appear darker green in color.
CA: Cell Bio 1f
The answer is A.
Chloroplasts are among
the plant organelles
known as plastids and
contain the green
pigment chlorophyll.
Chlorophyll traps light
energy from the Sun
and gives leaves and
stems their green color.
CA: Cell Bio 1f
Question 6
A mutation results in the inner membranes of a
liver cell's mitochondria being smooth, rather
than folded. Which of the following would you
expect?
A. more efficient storage of
cellular energy
B. It can create more
vesicles in a smaller
space
CA: Cell Bio 1g
Question 6
A mutation results in the inner membranes of a
liver cell's mitochondria being smooth, rather
than folded. Which of the following would you
expect?
C. decreased energy
available to the cell
D. fewer ribosomes
available for protein
synthesis
CA: Cell Bio 1g
The answer is C.
Mitochondria transform
energy for the cell. A
highly folded inner
membrane provides a
greater surface area for
producing energystoring molecules.
CA: Cell Bio 1g
Main Ideas
• Microscopes enabled biologists to see
cells and develop the cell theory.
• The cell theory states that the cell is the
basic unit of organization, all organisms are
made up of one or more cells, and all cells
come from preexisting cells.
Main Ideas Continued
• Using electron microscopes, scientists can
study cell structure in detail.
• Cells are classified as prokaryotic and
eukaryotic based on whether or not they have
membrane-bound organelles.
Main Ideas
• Through selective permeability, the plasma
membrane controls what enters and leaves a
cell.
• The fluid mosaic model describes the plasma
membrane as a phospholipid bilayer with
embedded proteins.
Main Ideas
• Eukaryotic cells have a nucleus and
organelles, are enclosed by a plasma
membrane, and some have a cell wall that
provides support and protection.
• Cells make proteins on ribosomes that are
often attached to the highly folded
endoplasmic reticulum. Cells store materials
in the Golgi apparatus and vacuoles.
Main Ideas Continued
• Mitochondria break down food molecules to
release energy. Chloroplasts convert light
energy into chemical energy.
• The cytoskeleton helps maintain cell shape, is
involved in the movement of organelles and
cells, and resists stress placed on cells.
Question 1
Which of the following is a main idea of the
cell theory?
A. All organisms are composed of one cell.
B. The organelle is the basic unit structure and
organization of organisms.
C. All cells come from two parent cells.
D. All cells come from preexisting cells.
CA: Biology/Life Sciences
1a-1j
The answer is D.
The cell theory states
that a cell divides to
form two identical
cells.
CA: Biology/Life Sciences
1a-1j
Question 2
In what type of cell would you find
chlorophyll?
A. prokaryote
B. animal
C. plant
D. fungus
CA: Biology/Life Sciences
1f
The answer is C.
Chlorophyll is the
green pigment found
in the chloroplasts of
plant cells.
CA: Biology/Life Sciences
1f
Question 3
Which of these structures packs proteins into
membrane-bound structures?
A.
B.
C.
D.
CA: Biology/Life Sciences
1e
Answer C depicts
the Golgi apparatus,
which sorts proteins
and packs them into
vesicles.
CA: Biology/Life Sciences
1e
Question 4
What is the
difference
between the cell
wall and the
plasma
membrane?
Cell wall
Inside
cell
Outside
cell
Plasma
membrane
CA: Biology/Life Sciences
1a, 1j
The plasma membrane is a
flexible boundary between the
cell and its environment that
controls the supply of nutrients,
waste, and other products
entering and leaving the cell.
The cell wall is a rigid structure
found in plant cells, fungi,
bacteria and some protists that
provides support and protection
but does not select which
molecules can enter or leave the
cell.
CA: Biology/Life Sciences
1a, 1j
Cell wall
Inside
cell
Outside
cell
Plasma
membrane
Question 5
Which of the following organelles is not
bound by a membrane?
A. ribosome
B. Golgi apparatus
C. vacuole
D. lysosome
CA: Biology/Life Sciences
1d
The answer is A.
Ribosomes are
simple structures
made of RNA and
protein and are not
bound by
membranes.
Ribosomes
CA: Biology/Life Sciences
1d
Question 6
Explain the
importance of
cholesterol to
the plasma
membrane.
CA: Biology/Life Sciences
1a, 1h
Phospholipid
molecules
Cholesterol
molecule
Cholesterol
helps to
stabilize the
phospholipids
in the plasma
membrane by
preventing
their fatty acid
tails from
sticking
together.
CA: Biology/Life Sciences
1a, 1h
Phospholipid
molecules
Cholesterol
molecule
Question 7
In which of the following pairs are the
terms related?
A. cell wall – selective permeability
B. prokaryote – mitochondria
C. microfilaments – locomotion
D. plastid – storage
CA: Biology/Life Sciences
1h
The answer is D.
Plastids are plant
organelles that are
used for storage.
CA: Biology/Life Sciences
1h
Question 8
Which of the following structures is found
in both plant and animal cells?
A. chloroplast
B. cell wall
C. mitochondrion
D. thylakoid membrane
CA: Biology/Life Sciences
1g
The answer is C.
Mitochondria are the
organelles in both
plant and animal
cells that transform
energy for the cell.
CA: Biology/Life Sciences
1g
Question 9
__________ span the entire plasma membrane
and regulate which molecules enter and leave the
cell.
A. Transport proteins
B. Cholesterol molecules
C. Ribosomes
D. Microtubules
CA: Biology/Life Sciences
1a
The answer is A. Transport proteins form the
selectively permeable membrane and move
needed substances or waste materials through
the plasma membrane.
CA: Biology/Life Sciences
1a
Question 10
Compare the cytoskeleton of a cell to the
skeleton of the human body.
CA: Biology/Life Sciences
1j
The cytoskeleton and skeleton are similar in
that both form a framework. However, the
cytoskeleton is a constantly changing structure
with the ability to be disassembled in one
place and reassembled in another.
CA: Biology/Life Sciences
1j
A prokaryotic cell does not have internal organelles
surrounded by a membrane. Most of a prokaryote’s
metabolism takes place in the cytoplasm.
2. DNA
1. Ribosomes
Click here
to return to
chapter
summary
CA: Biology/Life Sciences
1j
3. Plasma membrane
4. Cell wall
This eukaryotic cell from an animal has distinct
membrane-bound organelles that allow different parts
of the cell to perform different functions.
1. Nucleus
2. Nucleolus
3. Chromosomes
4. Plasma membrane
Click here
to return to
chapter
summary
CA: Biology/Life Sciences
1j
5. Organelles
Photo Credits
• Digital Stock
• PhotoDisc
• 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 7 Show