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Chapter 4
Cell Structure and Function
Table of Contents
Section 1 The History of Cell Biology
Section 2 Introduction to Cells
Section 3 Cell Organelles and Features
Section 4 Unique Features of Plant Cells
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Chapter 4
Section 1 The History of Cell Biology
Objectives
• Name the scientists who first observed living and
nonliving cells.
• Summarize the research that led to the development
of the cell theory.
• State the three principles of the cell theory.
• Explain why the cell is considered to be the basic
unit of life.
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Introduction to the Cell
• Definition – A cell is the smallest unit of structure
and function of living things that carries on life
processes.
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A. Discovery of the Cell
• Robert Hooke ( 1665) – 1st to see cells;
– looked at cork (dead plant cell);
– box-shaped structures looked like monk’s
rooms called ‘cells’.
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A. Discovery of the Cell
• Anton Van Leeuwenhoek (1673) – 1st to see living
cells.
– Scraped mouth: bacteria, yeast.
– Water: Protozoans, “Animalcules”.
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A. Discovery of the Cell
• Matthias Schleiden (1838) – Botanist,
– concluded all plants are made of cells.
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A. Discovery of the Cell
• Theodor Schwann (1839) – Zoologist,
– concluded all animals are made of cells
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A. Discovery of the Cell
• Rudolf Virchow (1855) – Physician,
– concluded cells come only from other living
cells.
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Chapter 4
Section 1 The History of Cell Biology
Cell Theory
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A. Discovery of the Cell
•
This information gave evidence for the Cell
Theory:
1. Cells are the basic unit of structure and function
in all living things.
2. All living things are made of cells.
3. Cells come only from the reproduction of other
living cells.
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Chapter 4
Section 1 The History of Cell Biology
The Cell Theory, continued
Think & Discuss:
• Cellular Basis of Life
– All living things are made of organized parts,
obtain energy from their surroundings, perform
chemical reactions, change with time, respond to
their environment, and reproduce.
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Chapter 4
Section 2 Introduction to Cells
Objectives
• Explain the relationship between cell shape and cell
function.
• Identify the factor that limits cell size.
• Describe the three basic parts of a cell.
• Compare prokaryotic cells and eukaryotic cells.
• Analyze the relationship among cells, tissues,
organs, organ systems, and organisms.
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B. Cell Diversity
1. Cell Size
– Most cells are only visible with microscope.
– Cell size varies from 2 m to .2m (.2 x 10-6)
– Examples:
• Bacteria - 0.2 m (.000008 in. or 8 millioneth
in.)
• Giraffe leg nerve – 2 m (6 ½ ft.)
• Eggs
• Most body and plant cells – 10 to 50 m
(.002 in.)
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Chapter 4
Section 2 Introduction to Cells
Think & Discuss:
• Cell Size
– Cell size is limited by a cell’s surface area–tovolume ratio.
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B. Cell Diversity
• Why are Cells so Small?
1. Diffusion is too slow to move nutrients &
wastes through cell.
2. As cell size increases, volume increases
at faster rate than surface area. Surface
area becomes too small to allow
materials to enter cell quickly enough to
meet its needs.
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B. Cell Diversity
2. Cell Shape
• The shape of a cell helps it to perform its function.
• Examples:
a. RBCs – concave, flexible – squeeze thru
vessels
b. WBCs – change shape – engulf particles
c. Nerves – long, threadlike, branched – receive &
send messages
d. Epithelial tissue – flat, packed – protection
e. Muscles – long, rod-like, contract – pull parts
together
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Chapter 4
Section 2 Introduction to Cells
Cell Diversity
• Cell Shape
– A cell’s shape reflects its function.
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Chapter 4
Section 2 Introduction to Cells
Cellular Organization
Think & Discuss:
• In multicellular eukaryotes, cells organize into tissues,
organs, organ systems, and finally organisms.
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How are organelles like organs?
• Organelles perform specific functions to keep a cell
healthy and alive.
• Organs perform specific functions to keep an
organism healthy and alive.
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Chapter 4
Section 2 Introduction to Cells
Two Basic Types of Cells
Think & Discuss:
• Prokaryotes
– Prokaryote cells
lack a nucleus and
membrane-bound
organelles.
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B. Cell Diversity
– Eukaryotes – cells that have a nucleus and
membrane-bound organelles.
– Prokaryotes – cells that lack a nucleus and have
no membrane-bound organelles. (bacteria)
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Chapter 4
Section 2 Introduction to Cells
Comparing Prokaryotes and Eukaryotes
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Chapter 4
Section 2 Introduction to Cells
Basic Parts of a Cell
Think & Discuss:
• The three basic parts of a cell are the plasma
membrane, the cytoplasm, and the nucleus.
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B. Cell Diversity
3. Internal Organization
a. Organelles – cell components that perform
specific functions to maintain the life of the cell.
b. Cell Membrane – Thin membrane surrounding
cell.
c. Nucleus – large organelle near center of cell;
contains genetic information; directs cell activities.
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Chapter 4
Section 3 Cell Organelles
and Features
Objectives
• Describe the structure and function of a cell’s plasma
membrane.
• Summarize the role of the nucleus.
• List the major organelles found in the cytosol, and describe their
roles.
• Identify the characteristics of mitochondria.
• Describe the structure and function of the cytoskeleton.
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Chapter 4
Section 2 Introduction to Cells
Internal Organization of a Cell
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Chapter 4
Section 2 Introduction to Cells
Basic Parts of a Cell, continued
•
Cytoplasm - (Cytosol)
a. Located between cell membrane & nucleus
b. Contains gel-like fluid called Cytosol and
organelles.
c. Helps give shape to cell.
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B. Organelles:
a. Organelles – cell components that perform
specific functions to maintain the life of the cell.
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Chapter 4
Section 3 Cell Organelles
and Features
Endoplasmic Reticulum (“E.R.”)
a.
b.
c.
d.
Intracellular “Highway”
Membranous tubes used to transport molecules
Rough ER – has ribosomes; transports proteins
Smooth ER – no ribosomes; makes lipids
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Chapter 4
Section 3 Cell Organelles
and Features
Endoplasmic Reticulum, continued
• The smooth ER builds lipids and participates in
detoxification of toxins.
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Chapter 4
Section 3 Cell Organelles
and Features
Endoplasmic Reticulum (ER) and Ribosomes
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Chapter 4
Section 3 Cell Organelles
and Features
Ribosomes
• Ribosomes
a. site of protein synthesis
b. Located on rough E.R. and scattered
throughout cytoplasm
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Chapter 4
Section 3 Cell Organelles
and Features
Ribosomes
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Chapter 4
Section 3 Cell Organelles
and Features
Golgi Apparatus (“Packing & Shipping”)
a. Stack of flat membranous sacs.
b. Packages proteins from the ER
c. Secretes (‘ships’) them to other parts
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Chapter 4
Section 3 Cell Organelles
and Features
Mitochondria
• Mitochondria (“Powerhouse”)
a. site of cellular respiration- make ATP energy
from glucose
b. inner membrane has many folds (Cristae) to
increase surface area
c. large numbers found in muscle cells
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Chapter 4
Section 3 Cell Organelles
and Features
Mitochondria
• Mitochondria harvest energy from organic
compounds and transfer it to ATP.
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Chapter 4
Section 3 Cell Organelles
and Features
Mitochondrion
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Chapter 4
Section 3 Cell Organelles
and Features
Vesicles
•
(Vesicles, including lysosomes (digestive
enzymes) and peroxisomes (detoxification
enzymes), are classified by their contents.)
Lysosomes (“Cleaning Crew”)
a. Sac of digestive enzymes
b. Break down nutrients, invaders, debris
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Chapter 4
Section 3 Cell Organelles
and Features
Processing of Proteins
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Chapter 4
Section 3 Cell Organelles
and Features
Cytoskeleton
•
(The cytoskeleton is made of protein fibers that
help cells move and maintain their shape.)
Cytoskeleton
a. Microfilaments – fine protein threads
• Ex: Actin – cause muscles to contract
b. Microtubules – hollow protein tubes
• Ex: Spindle Fibers – move chromosomes
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Chapter 4
Section 3 Cell Organelles
and Features
Cytoskeleton
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Chapter 4
Section 3 Cell Organelles
and Features
Cytoskeleton, continued
Think & Discuss:
•
Cilia and Flagella
– (Cilia and flagella are hairlike structures that
extend from the surface of the cell, where they
assist in movement.)
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Chapter 4
Section 3 Cell Organelles
and Features
Cytoskeleton, continued
Cilia
a. Tiny hair-like projections on cell membrane
packed in rows
b. Wave, move mucus, catch debris
Flagella
a. Long, whip-like, on cell surface
b. Allow sperm cells to swim
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Chapter 4
Section 3 Cell Organelles
and Features
Structure of Cilia and Flagella
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Chapter 4
Section 3 Cell Organelles
and Features
Cytoskeleton, continued
• Centrioles
– A. two short cylinders of microtubules at right
angles to each other
– B. involved in cell division.
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Chapter 4
Section 3 Cell Organelles
and Features
Nucleus
• Nucleus
a. Contains DNA (genetic info) – directs cell’s activities
b. Located near center of cell
c. Nuclear Envelope – porous, double membrane
d. Nucleolus – produces ribosomes
e. Chromatin – “thread-like” DNA
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Chapter 4
Section 3 Cell Organelles
and Features
Nucleus of a Cell
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Chapter 4
Section 2 Introduction to Cells
Parts of the Eukaryotic Cell
A. Cell Membrane
Next, we’ll discuss:
• Plasma Membrane
– (The cell’s outer boundary, called the plasma
membrane (or the cell membrane), covers a cell’s
surface and acts as a barrier between the inside
and the outside of a cell. )
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Chapter 4
Section 3 Cell Organelles
and Features
Plasma Membrane, continued
Think & Discuss:
• Membrane Proteins
– Cell membranes often contain proteins embedded
within the phospholipid bilayer.
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Chapter 4
Section 2 Introduction to Cells
Parts of the Eukaryotic Cell
A. Cell Membrane
– Selectively Permeable – controls which
substances pass into and out of cell.
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Chapter 4
Section 2 Introduction to Cells
Parts of the Eukaryotic Cell
A. Cell Membrane
1. Membrane Lipids – lipids (fats) allow fatsoluble substances to pass through
2. Phospholipids form a lipid bilayer.
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Chapter 3
Section 3 Cell Organelles
and Features
Structure of
Lipid Bilayer
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Chapter 4
Section 3 Cell Organelles
and Features
Cell Membrane
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Chapter 4
Section 2 Introduction to Cells
Parts of the Eukaryotic Cell
A. Cell Membrane
3. Membrane Proteins – allow fat-nonsolubles to
pass through
4. Fluid Mosaic Model – lipid bilayer behaves
more like a fluid than a solid. Lipids and
proteins can move (fluid) within bilayer, so
their pattern (mosaic) changes.
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Chapter 4
Section 2 Introduction to Cells
Basic Parts of a Cell
Do You Remember?
• The three basic parts of a cell are:
The plasma membrane, cytoplasm, and nucleus.
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Chapter 4
Section 2 Introduction to Cells
Do you Remember:
The Two Basic Types of Cells?
• Prokaryotes
– Prokaryote cells
lack a nucleus and
membrane-bound
organelles.
(Bacteria)
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•
Eukaryotes –
cells that have a
nucleus and
membrane-bound
organelles.
(Animals, Plants,
Fungus, Protist)
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Chapter 4
Section 4 Unique Features
of Plant Cells
Objectives
• List three structures that are present in plant cells but not in
animal cells.
• Compare the plasma membrane,the primary cell wall, and the
secondary cell wall.
• Explain the role of the central vacuole.
• Describe the roles of plastids in the life of a plant.
• Identify features that distinguish prokaryotes, eukaryotes,
plant cells, and animal cells.
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Chapter 4
Section 4 Unique Features
of Plant Cells
Plant Cells
• Plant cells have cell walls, central vacuoles, and
plastids.
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Chapter 4
Section 4 Unique Features
of Plant Cells
A. Cell Wall
• A solid, rigid, outer covering; provides support and
protection.
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Chapter 4
Section 4 Unique Features
of Plant Cells
Parts of a Cell Wall
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Chapter 4
Section 4 Unique Features
of Plant Cells
B. Central Vacuole
1. Storage areas- store water, enzymes, and waste
products and provide support for plant tissue.
2. Large – up to 90% of cell’s volume
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Chapter 4
Section 4 Unique Features
of Plant Cells
C. Plastids
1. Store starch, fats, or pigments
2. Chloroplast – contains chlorophyll for
photosynthesis
3. Leucoplast – stores starch
4. Chromoplast – makes & stores pigments:
Carotene – orange;
Xanthrophyll – yellow
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Chapter 4
Section 4 Unique Features
of Plant Cells
Chloroplasts
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Chapter 4
Section 4 Unique Features
of Plant Cells
Comparing Cells
• Prokaryotes, animal cells, and plant cells can be
distinguished from each other by their unique
features.
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Chapter 4
Section 4 Unique Features
of Plant Cells
Comparing Plant and Animal Cells
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Chapter 4
Standardized Test Prep
Multiple Choice
1. The eukaryotic nucleus houses all of the following
except the
A. RNA
B. DNA
C. nucleolus
D. endoplasmic reticulum
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
1. The eukaryotic nucleus houses all of the following
except the
A. RNA
B. DNA
C. nucleolus
D. endoplasmic reticulum
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
2. Which structure contributes to support and movement
within a cell?
F. crista
G. cell wall
H. ribosome
J. microfilament
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
2. Which structure contributes to support and movement
within a cell?
F. crista
G. cell wall
H. ribosome
J. microfilament
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
3. Which of the following statements about RNA is true?
A. RNA is found only in proteins.
B. RNA is found only in the nucleus.
C. RNA is found only in the cytoplasm.
D. RNA is found in the nucleus and cytoplasm.
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
3. Which of the following statements about RNA is true?
A. RNA is found only in proteins.
B. RNA is found only in the nucleus.
C. RNA is found only in the cytoplasm.
D. RNA is found in the nucleus and cytoplasm.
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The graph below shows
the relationship between cell size
and surface area–to–volume ratio.
Use the graph below to answer
the questions that follow.
4. By what percentage does
the surface area–to –
volume ratio change when
a cell grows from 1 to 2 µm
in diameter?
F. 10 percent
G. 20 percent
H. 50 percent
J. 90 percent
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The graph below shows
the relationship between cell size
and surface area–to–volume ratio.
Use the graph below to answer
the questions that follow.
4. By what percentage does
the surface area–to –
volume ratio change when
a cell grows from 1 to 2 µm
in diameter?
F. 10 percent
G. 20 percent
H. 50 percent
J. 90 percent
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The graph below shows
the relationship between cell size
and surface area–to–volume ratio.
Use the graph below to answer
the questions that follow.
5. What is the maximum
diameter that this cell could
attain before the surface
area–to-volume ratio would
fall below 1?
A. 2 µm
B. 5 µm
C. 10 µm
D. 15 µm
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The graph below shows
the relationship between cell size
and surface area–to–volume ratio.
Use the graph below to answer
the questions that follow.
5. What is the maximum
diameter that this cell could
attain before the surface
area–to-volume ratio would
fall below 1?
A. 2 µm
B. 5 µm
C. 10 µm
D. 15 µm
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
6. mitochondria : energy release :: ribosome :
F. cell support
G. protein synthesis
H. cellular digestion
J. cellular transport
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
6. mitochondria : energy release :: ribosome :
F. cell support
G. protein synthesis
H. cellular digestion
J. cellular transport
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The figure below shows
a diagram of a cell. Use the
figure to answer the
question that follows.
7. What is the function of the
structure labeled 1?
A. to make ATP
B. to make proteins
C. to make carbohydrates
D. to move proteins through
the cell
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Chapter 4
Standardized Test Prep
Multiple Choice, continued
The figure below shows
a diagram of a cell. Use the
figure to answer the
question that follows.
7. What is the function of the
structure labeled 1?
A. to make ATP
B. to make proteins
C. to make carbohydrates
D. to move proteins through
the cell
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Chapter 4
Standardized Test Prep
Short Response
A cell’s shape is generally related to its function.
Skin cells are flat and platelike. Nerve cells have long
extensions. Explain the relationship between the
shape of skin and nerve cells and their function in the
body.
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Chapter 4
Standardized Test Prep
Short Response, continued
Answer:
Cell shape reflects the different functions of cells. For
example, the long extensions of nerve cells allow
these cells to receive and transmit nerve impulses in
many directions. Also, the flat shape of skin cells
suits their function of covering and protecting the
surface of the body.
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Chapter 4
Standardized Test Prep
Extended Response
Despite the diversity among cells, eukaryotic cells
share many common features.
Part A Describe the structure and function of the
organelles found in an animal cell.
Part B Summarize the differences that distinguish
animal cells from bacteria and plant cells.
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Chapter 4
Standardized Test Prep
Extended Response, continued
Answer:
Part A Answers may include the following: The nucleus holds
and protects DNA; Mitochondria transfer energy to ATP;
Ribosomes manufacture proteins; The ER functions as an
intracellular highway; The Golgi apparatus directs proteins
to other parts of the cell; Vesicles digest materials, break
down old cells, and play a role in protein synthesis.
Part B Plant and bacterial cells, unlike animal cells, have
a cell wall. Bacterial cells, unlike plant and animal
cells, lack a membrane-bound nucleus and
organelles. Some bacterial cells and all plant cells
have plastids.
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