Cells:
The Basic Units of Life
Teacher's Guide
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Cells:
The Basic Units of Life
Teacher's Guide
catalog #2113
Video Produced by ...
Chariot Productions
Published & Distributed by…
AGC/UNITED LEARNING
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CELLS: THE BASIC UNITS OF LIFE
RUNNING TIME: 24 MINUTES
PROGRAM SUMMARY
This program introduces seventh through ninth grade
students to the world of the cell. It is also appropriate for
more advanced students because of the depth of the information presented.
The first half of the program examines the relationship
between cells and living organisms. Examples are provided beginning with the simplest free-living cells of the
unicellular bacteria and protozoa up through the complex
arrangements of cells that form the tissues of multicellular
plants and vertebrate animals. Some history relating to the
discovery of cells and the origin of the "Cell Theory" is also
presented in this section.
The second half of the program is a journey through a
typical cell from its nucleus to cell membrane. Each important subcellular structure is identified and its function is
described. Animation is used in this section to provide a
clear understanding of the relationship between subcellular organelles and specific cell functions. The differences
between animal and plant cells are also presented throughout the second part of the program.
An optional ten-question Interactive Video Quiz follows
the conclusion of this program (the quiz is also provided on
Blackine Master 7). Suggestions for its use are given under
Teacher Preparation on pages 2 & 3.
For your teaching convenience, a script of the video narration is provided in this Teacher's Guide beginning on page
12.
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STUDENT OBJECTIVES
After viewing this program and participating in the learning activities, students should be able to…
• Describe what cells are.
• Name the seven characteristics of all living things.
• Name the parts of a cell and describe the function of each
part.
• Summarize the major differences between the cells of
animals and those of plants.
• Trace the steps and identify the cell structures involved
in the creation, distribution, and export of proteins.
SUGGESTED LESSON GUIDE
TEACHER PREPARATION
1. Read and review this guide and preview the video
before showing it to your class.
2. Read and review the blackline masters and duplicate
those you choose to use.
3. NOTE: At the end of this video presentation, there is an
Interactive Video Quiz for use in one of several ways:
• The quiz is also provided on Blackline Master 7. You
can distribute it prior to its presentation on the video and
have students answer as the questions are posed. It is your
choice as to whether you want them to answer verbally as
each question is asked or whether you prefer that each
student answer on a sheet of paper.
• You may choose to use the Interactive Video Quiz as a
study guide. If so, distribute Blackline Master 7 before the
viewing with instructions that students read the questions
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first to become familiar with the video content. The students can then be listening for the correct answers during
the video presentation.
• You could choose to use Blackline Master 7, Interactive
Video Quiz, as a review on another day.
Note: The Interactive Video Quiz is not intended to be used for
evaluation purposes. A 3-part Lesson Quiz is provided on
Blackline Masters 8, 9, & 10).
4. Make arrangements to have a VHS player and television set available for use at the time and place selected for
viewing.
5. Arrange to have microscopes available for student use.
6. Purchase, or obtain from school collections, the following prepared slides: Allium (onion) root tip mitosis and
Basal Ganglion cells stained for the Golgi apparatus.
7. Obtain the living cells of the giant ameba Chaos chaos
(Pleomyxa) from a biological supply house. Order these
about two weeks before you anticipate using them in class.
BLACKLINE MASTER DESCRIPTIONS
(An Answer Key for those Blackline Masters that require answers is provided on pages 6, 7, & 8.)
Blackline Masters 1 & 2, Vocabulary List, is a list of words
used in the video and their definitions. This list can be
distributed to the class before the video presentation so
students can better understand the terms presented. This
list should be retained by students for reference. The list
has also been included in this Teacher's Guide on pages 912.
Blackline Masters 3 and 3a are diagrams of A Typical
Animal Cell.
Blackline Masters 4 and 4a are diagrams of A Typical
Plant Cell.
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Blackline Master 5 is a diagram of Pathways Within the
Cell.
Blackline Master 6, Crossword Puzzle, gives students an
opportunity to use some of the terms introduced in the
video.
Blackline Master 7, Interactive Video Quiz, is a copy of
the questions posed in the interactive video instructional
quiz at the end of the video. Suggestions for its use are
described under Teacher Preparation on pages 2 & 3.
Answers to the quiz are provided on pages 21& 22.
Blackline Masters 8, 9, & 10 provide a three-part Lesson
Quiz for student evaluation. The EssayQuestions portion
of the quiz can be used for extra credit.
INTRODUCING THE PROGRAM
Introduce this program by telling the students that they are
about to enter a very strange and mysterious world--a
world that is remote from their day-to-day experience but
upon which their lives depend.
Let them know that all living things are made up of one or
more cells which are so small that one billion average-sized
cells could fit into a one cubic inch container.
Make the students aware that fully-grown human beings
are composed of about one hundred trillion cells of many
different types--yet each is capable of living an independent life if provided with the proper environment (such as
is possible in the culturing of human cells in vitro).
Emphasize that in the tour of the cell they are about to take,
they will be looking at life in its most elementary and basic
form.
Before starting the video, distribute the blackline masters
you've chosen to use during the video presentation., e.g.
Blackline Masters 1 & 2, Vocabulary List, and Blackline
Master 7, Interactive Video Quiz. (Uses for the Interac4
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tive Video Quiz are described on pages 2 & 3 under
Teacher Preparation.) If you've chosen to use the Interactive Video Quiz, you should inform the students that they
will be expected to answer the questions which will appear
on the screen following the program.
VIDEO PRESENTATION
Viewing time: 24 minutes
FOLLOW-UP ACTIVITIES
Discussion
1. Discuss the fact that all living things are made of cells.
Ask "What are the characteristics of living things?" Answer:
1) Grow 2) Repair and maintain themselves 3) Reproduce 4)
Undergo change 5) Move 6) Respond to surroundings 7) Grow
old and die.
2. Discuss the flow of information in the cell from DNA to
RNA to protein. Talk about the role of proteins in the body,
for example, the hemoglobin of red blood cells, the enzymes that are needed not only to digest food but that are
also involved in regulating every biochemical reaction that
takes place within the cell, the collagen for connective
tissue, the keratin for hair, and the actin and myosin for
muscle fiber, etc.
3. Discuss the concept of "one gene/one protein" and
contrast to the classical notion of genes (such as the genes
for hair color, blood type, etc.)
4. Point out that all of the different types of cells in the
body were derived from the single cell of a fertilized egg by
the process called cellular differentiation. Speculate as to
how, from the point of view of the information contained
in the DNA, this differentiation might have occurred.
5. Discuss the cell membrane's role in diffusion, osmosis,
active transport, and the uptake of food by phagocytosis
and endocytosis.
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6. Discuss the cell theory of the 19th century. Answers
should include: All living things are made up of cells. Cells are
the basic structural units of life. All cells come from other cells.
Projects
1. Microscopic Examination of Non-Living Cells
PLANT CELLS: Have students examine stained and prepared slides of the root tip cells of an onion. Ask them to
locate the nucleus, cytoplasm, cell wall, cell membrane,
and chromosomes.
ANIMAL CELLS: In the trigeminal ganglion cells stained
for the Golgi apparatus, locate the nucleus, nucleolus,
cytoplasm, Golgi apparatus, and cell membrane.
When students have completed these microscopic examinations, discuss the differences between the cells of animals and those of plants.
2. Microscopic Examination of a Living Cell
Using the living cells of the giant ameba Chaos chaos
(Pleomyxa), locate the vacuoles, pseudopodia, nuclei (this
is a multi-nucleate organism), cytoplasm, and cell membrane. A few students may be lucky enough to observe an
ameba feeding by phagocytosis or undergoing reproduction by binary fission.
Typically, paramecia are also present in cultures of Chaos
chaos. Locate their cilia and observe their contractile
vacuoles in action under high power.
BLACKLINE MASTER ANSWER KEY
Blackline Master 3, Crossword Puzzle
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Blackline Master 7, Interactive Video Quiz answers can
be found on pages 20 & 21
Blackline Master 8, Lesson Quiz, Part 1
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
I
J
A
G
F
D
C
E
B
H
Blackline Master 9, Lesson Quiz, Part 2
True Or False
1. F - Some, such as those living in our intestines, are
beneficial.
2. T
3. F - The basic principles of that theory are still accepted
today.
4. F - They are in continuous motion.
5. T
Fill In The Blank
1. cells
2. 1) grow
2) repair and maintain themselves
3) reproduce
4) undergo change
5) move
6) respond to their surroundings
7) grow old and die
3. unicellular
4. multicellular
5. life
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Blackline Master 10, Lesson Quiz, Part 3, Essay Questions
Answers will vary but should include the following information:
1. Explain how, nearly four hundred years ago, cells came
to be named.
Almost 400 years ago, while using a simple microscope to study
slices of dried plant tissue, the English scientist, Robert Hooke,
saw structures that reminded him of the tiny sleeping rooms
called "cells" used by monks that he had seen in medieval
monasteries.
2. Briefly explain Theodore Schwann's and M. J. Schlieden's
"Cell Theory."
It consists of three parts: First, that all living things are made up
of cells; second, that cells are the basic structural and functional
units of life; and third, that all cells come from other cells.
3. Certain differences exist between the structure of animal and plant cells. Write a few paragraphs that compare
and contrast animal and plant cells.
Very briefly some of the likes and differences in the structure of
animal and plant cells…
• Plants get their green color from pigment called chlorophyll
that is found in special cytoplasmic organelles, called chloroplasts, that are absent in animal cells.
• Animal cells possess tiny structures called centrioles, or
centrosomes, that are the focal point for the spindle fibers found
in dividing animal cells. Plant cells have spindle fibers but rarely
have centrioles and are able to reproduce perfectly well without
them.
• Both animal and plant cells contain large water-filled sacs
called vacuoles.
• Animal cells, but not plant cells, have many small rounded
structures called lysosomes that are very similar to the food
vacuoles of protozoa.
• Plants possess a tough outer non-living layer called a cell
wall, whereas animals lack a cell wall.
• Both plants and animals possess a thick cell membrane, also
called a plasmalemma or plasma membrane, that is very important to each type of cell.
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VOCABULARY LIST
Cell The smallest biological unit capable of carrying out all
of the fundamental activities of life. The basic unit of
structure and function of any living thing.
Cell Membrane The thin, flexible layer that surrounds a
cell and which controls all that enters and leaves the cell.
Cell Wall In plant and bacterial cells, the outermost nonliving cellulose layer that surrounds the entire cell, including the cell membrane.
Centriole In animal cells, a structure outside the nucleus
that organizes the spindle fibers during cell reproduction.
Centrosome Another name for the centriole.
Chlorophyll A green pigment found in the chloroplasts of
plant cells that is essential for photosynthesis.
Chloroplasts The chlorophyll-containing organelles found
in the cytoplasm of plant and algae cells.
Chromatin The coils of DNA and protein that condense to
form chromosomes. Chromatin can be thought of as
chromosomes with no distinct shape.
Chromosomes Distinct wormlike cell structures formed
from chromatin during cell reproduction.
Contractile Vacuoles Large sacs found in the cells of
certain protozoans that remove the water that has accumulated inside the cell by pumping it to the outside of the cell.
Cilia Hairlike structures found on the outside of certain
cells. The protozoans called ciliates use cilia to propel
themselves through the water in which they live.
Cytoplasm That part of a cell's protoplasm that lies outside
of its nucleus.
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Deoxyribonucleic Acid (DNA) A large and very complex
biochemical that stores the information needed to construct proteins and that carries the genetic information
about an organism.
DNA The abbreviation for deoxyribonucleic acid.
Endoplasmic Reticulum The intricate system of tubes
leading from the nuclear membrane into the cytoplasm
that is involved in transporting proteins.
Enzyme A special class of proteins that control the rates of
biochemical reactions.
Flagellum A long, whiplike cell structure used to propel
sperm cells as well as the cells of the protozoans known as
flagellates.
Food Vacuoles The sacs where food particles are digested
that are found in the cytoplasm of protozoan cells.
Gene The basic unit of heredity, made up of a specific
region on a DNA molecule. Also a specific region of a DNA
molecule that holds the code for one specific protein.
Golgi Apparatus A subcellular organelle involved in
packaging proteins for export from the cell.
Lysosomes In animal cells, the organelles where large
food molecules are broken down into smaller, more useful,
food molecules.
Microtubules Tiny tubules inside the cell that form the
cell's internal "cytoskeleton" and that help rearrange structures inside the cell.
Mitochondria The organelles known as the "power houses
of the cell" where the stored energy of food is made
available for use within the cell.
Multicellular A word used to describe organisms made
up of many cells.
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Nuclear Membrane A layer inside the cell that surrounds
the nucleus and contains many tiny pores.
Nucleus A large structure within the cell that contains
chromatin, the nucleolus, and is surrounded by a nuclear
membrane.
Nucleolus The "little nucleus" found inside the nucleus
which is made up of RNA and protein.
Organelle A tiny cell structure; a miniature organ. Ribosomes, mitochondria, and chloroplasts are all organelles.
Phagocytosis A method by which cells take in food by
surrounding and engulfing it. Amebae and white blood
cells take in food by this method.
Photosynthesis The process by which plant cells make
food and oxygen from water, carbon dioxide, and sunlight.
Plasma Membrane Another name for the cell membrane.
Plasmalemma Another name for the cell membrane.
Protein A class of biochemicals made up of amino acids
that can be important in building and repairing cells or in
controlling chemical reactions inside the cell.
Protoplasm All the living materials inside a cell.
Ribonucleic Acid (RNA) A class of nucleic acids that can
be used either in reading the genetic information on the
DNA or in guiding the process of making proteins.
Ribosomes The organelles where proteins are assembled.
RNA The abbreviation for ribonucleic acid.
Spindle Fibers Microtubules visible during cell division
that are involved in separating chromosomes into two
separate identical groups.
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Tissue Layers of closely related cells that work together to
perform a specific function, such as muscle tissue, liver
tissue, nervous tissue, etc.
Unicellular An organism composed of just one cell.
SCRIPT OF VIDEO NARRATION
CELLS: THE BASIC UNITS OF LIFE
Living things, from the simplest microscopic organisms,
up through the largest, most complex animals and plants,
are alike in one basic respect: All of them are made up of
cells.
Most cells are so small they can only be seen by looking
through a microscope, and, by using powerful electron
microscopes, scientists have discovered that these tiny
cells are themselves made up of many highly-organized
components.
All living cells can grow, repair and maintain themselves,
reproduce, undergo change, move, respond to their surroundings, and all living cells will eventually grow old and
die.
Because cells are the smallest biological structures capable
of performing all of these life activities, they are called "the
basic units of life."
In this program, we will learn what cells are, what their
components are, and how these components work together to carry out the unique activities of life.
UNICELLULAR ORGANISMS
Many of nature's simplest creatures are nothing more than
single, independently living cells and, therefore, are called
"unicellular organisms."
By looking at a drop of pond water under a microscope, we
can see some of these free-living cells.
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The smallest and most primitive living cells are the bacteria
we see here.
Some bacterial cells are dangerous to humans and can
cause infections, such as strep throat and tuberculosis,
while other bacteria, such as those that live in our intestines, are beneficial.
Larger and more complicated free-living cells found in a
drop of pond water are the protozoa seen here.
Protozoan cells come in many different sizes, shapes, and
colors.
Because they live as independent organisms, many protozoans have developed special cell structures that allow
them to move through the water in search of food.
The cell of a paramecium is covered with tiny hair-like
structures called cilia, which rapidly beat the water, resulting in cell locomotion.
An ameba slides over surfaces by extending out parts of its
cell, called pseudopods, or false feet, which then pull the rest
of the cell along behind them.
And this protozoan uses a whip-like flagellum to move its
cell through the water.
MANY-CELLED ORGANISMS
Cells of many protozoans gather together to form colonies
of identical cells.
The Volvox seen here is one such colony of cells.
But in larger, more biologically advanced creatures, called
"multicellular organisms," many different kinds of cells are
joined together to perform specialized tasks.
Generally speaking, the more cells a multicellular organism possesses, the larger its body will be. For example, it
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is estimated that an adult human being is made up of about
one hundred trillion cells--whereas a smaller multicellular
organism, such as a butterfly, would have only a few
billion cells.
Within the bodies of multicellular organisms, most cells of
the same type will join together to form layers, called
tissues.
Tissue layers of different cell types can be very clearly seen
in this stained section of a frog's stomach.
The reddish tissue layer seen here is made up of smooth
muscle. These specialized cells are quite long and thin and
can contract to help move food down the digestive tract.
And these thick rectangular epithelial cells that make up
the stomach's lining are specialized to release chemicals
into the stomach sac to help digest food.
Plants have tissues just like animals do.
Here in this section of a plant stem, many distinct layers of
cells can be very clearly seen, and they tell an interesting
story about how cells were discovered.
Almost four hundred years ago, while using a simple
microscope like this to study slices of dried plant tissue, the
English scientist, Robert Hooke, saw structures that reminded him of the tiny sleeping rooms, called "cells," used
by monks that he had seen in medieval monasteries.
So it was, through this unlikely connection, that cells, the
basic units of life, were named.
For over two centuries after their discovery, scientists
debated the importance and function of cells.
Then, around 1839, two German scientists, Theodore
Schwann and M. J. Schlieden, came up with a theory to
explain the role of cells in living things.
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The "Cell Theory" of Schlieden and Schwann consists of
three parts: First, that all living things are made up of cells;
second, that cells are the basic structural and functional
units of life; and third, that all cells come from other cells.
Today scientists still accept the basic principles of this early
nineteenth century theory.
And now many wonderful new scientific instruments,
especially the electron microscope, have allowed contemporary biologists to probe deeply within cells to unlock
some of the mysteries they contain.
THE STRUCTURE OF CELLS
The basic material of all living cells is a jelly-like substance
called protoplasm. The protoplasm of the simplest living
creatures, such as bacteria, lacks the complicated structures found in more advanced organisms.
But the protoplasm that makes up the cells of fungi, protozoa, plants and animals is divided into two basic parts,
easily distinguishable under a light microscope, namely a
nucleus and the cytoplasm that surrounds it.
Let us look more closely at the cytoplasm and nuclei of
some of these more advanced calls.
THE NUCLEUS
The nucleus is normally an oval or spherical structure
found near the center of the cell.
The nucleus is very important because it is the control
center for the entire cell. The nucleus regulates and directs
all of the cell's activities--from how it reproduces to how it
uses food.
In cells that are not dividing, the interior of the nucleus is
filled with threadlike coils called chromatin that is made up
of protein and a huge information storage molecule called
DNA, short for deoxyribonucleic acid.
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Special areas of the giant DNA molecule, called genes, hold
the information needed to construct proteins that are used
to build and repair cells and are also critical to all normal
cell functions.
The DNA also carries the hereditary characteristics of a
cell. In the case of a unicellular organism, like this paramecium, the genes of its DNA contain all the information
needed to make a new paramecium that is an exact copy of
the original parent cell.
During cell reproduction, when two cells are formed from
one cell, the chromatin condenses to form little worm-like
structures called chromosomes that, having been duplicated, slide into the newly-forming cells…and then change
back into chromatin again.
In this way, the hereditary characteristics of the cell are
passed from one generation to the next.
Inside of the nucleus, along with the chromatin, is a small
rounded object called the nucleolus or "little nucleus."
The nucleolus is very dense and contains a large amount of
a chemical similar to DNA, called RNA, or ribonucleic acid.
The special kind of RNA found in the nucleolus, called
ribosomal RNA, passes into the cytoplasm through pores in
the nuclear membrane that surrounds the nucleus.
CYTOPLASMIC CELL STRUCTURES
Here in the cytoplasm, the ribosomal RNA forms hundreds of thousands of tiny organs, or organelles, called
ribosomes.
It is on the surface of the ribosomes that the directions for
making new proteins, that arrive from the DNA in the form
of another kind of RNA called messenger RNA, are translated as new proteins are formed.
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Most, but not all, of the ribosomes in the cytoplasm are
found attached to a very complicated system of flattened
tubes called the endoplasmic reticulum.
The proteins made by the ribosomes in one part of the cell
can pass through the tubes of the endoplasmic reticulum
on their way to other parts of the cell.
Some cells actually export the proteins they make. These
types of cells usually have a special system of tubular
membranes, called the Golgi apparatus, which seems to be
part of the endoplasmic reticulum, and that helps "package" proteins for transport outside of the cell.
The Golgi apparatus even works in the opposite direction
as it transports substances already inside the cell into the
tubes of the endoplasmic reticulum.
Spread throughout the cytoplasm are other organelles,
much larger than ribosomes, called mitochondria. Some
cells, such as human liver cells, may possess a thousand or
more mitochondria.
The mitochondria are known as the "powerhouses of the
cell," for within the tiny folds of these organelles, food
materials, like sugars, are converted into special energyrich molecules used by the cell to power its life processes.
Because the mitochondria contain a small amount of DNA-enough for about fifty genes--some biologists believe that
mitochondria, developed millions of years ago as very
simple free-living organism similar to bacteria, invaded
other living cells and then took up permanent residence
inside of them.
PLANT CELLS VERSUS ANIMAL CELLS
As might be expected, certain differences exist between the
structure of animal and plant cells.
Plants get their green color from a pigment called chlorophyll that is found in special cytoplasmic organelles, called
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chloroplasts, that are absent in animal cells.
Within the chloroplasts of plants, the energy of the sun is
captured as carbon dioxide and water are chemically combined to create sugars and oxygen by a process called
photosynthesis.
Plants, and animals that eat plants, then use these sugars
for food.
Like mitochondria, chloroplasts are believed to have developed from simple organisms that took up residence
inside of other larger cells.
The possibility of such an event occurring is not as unlikely
as it might seem. Today single-celled, plant-like algae that
can carry out photosynthesis are commonly found dwelling in the cytoplasm of the large cell of the protozoan,
called stentor, seen here.
These algae presumably escaped being digested to assume
a symbiotic relationship with the stentor. As a result of this
mutually beneficial relationship, the stentor obtains food
and oxygen from the algae in its cytoplasm, and the algae
are protected from creatures that might eat them in the
outside environment.
Another difference between the cells of plants and animals
is that animal cells possess tiny structures called centrioles,
or centrosomes, that are the focal point for the spindle fibers
found in dividing animal cells.
Plant cells have spindle fibers but rarely have centrioles
and are able to reproduce perfectly well without them.
The spindle fibers found in dividing cells attach to the
doubled chromosomes and then separate them into two
equal groups.
Spindle fibers are composed of the microtubules that make
up a large part of the cell's cytoskeleton. Microtubules are
very important in controlling both the shape and the
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internal arrangement of the organelles within a living cell.
Both animal and plant cells also contain large water-filled
sacs called vacuoles.
Very often, plants will have just one large vacuole…whereas
animal cells will usually have several, much smaller, vacuoles.
When the vacuoles of plant cells are filled with water, the
plant and its leaves will be fairly rigid, but in the absence
of water, the vacuoles empty out and the plant wilts.
Here we see a contractile vacuole forming in a paramecium
cell.
These vacuoles slowly fill up with water that accumulates
inside the cell and then pump it to the outside. By doing
this, contractile vacuoles prevent cells from blowing apart.
In this ameba cell, food vacuoles form as pseudopods surround particles of food material in a process called phagocytosis.
Digestion takes place inside of these food vacuoles in most
unicellular organisms, and after digestion is complete,
these vacuoles are filled up with undigested waste that is
then released to the outside of the cell.
Animal cells, but not plant cells, have many small rounded
structures called lysosomes that are very similar to the food
vacuoles of protozoa.
Lysosomes contain digestive enzymes. Within them large
food molecules are broken down into smaller molecules
that can then be used by the mitochondria to produce
energy for the cell.
Lysosomes also help organisms get rid of dead and dying
cells. When a tadpole begins to lose its tail as it is transformed into a tail-less adult frog, the lysosomes within the
tail cells carry out this job.
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One other major difference between the cells of animals
and those of plants is that plants possess a tough outer nonliving layer called a cell wall, whereas animals lack a cell
wall.
The cell walls of plants join together to create rigid layers
allowing trees and other large plants to grow tall and
upright.
Both plants and animals possess a thin cell membrane, also
called a plasmalemma or plasma membrane, that is very
important to each type of cell.
In plant cells, the cell membrane is found just inside of the
cell wall, whereas in animals, the cell membrane creates the
outer boundary of each individual cell.
The cell membrane is a highly organized structure that
performs a number of very important tasks. Everything
the cell needs, including food, water, and oxygen, must
pass through this membrane to enter the cell.
Likewise, waste products exit the cell through this membrane.
By controlling what enters and leaves the cell, the cell
membrane helps maintain a state of perfect balance within
the cell, called homeostasis.
In animal and many protozoan cells, the cell membrane
also performs the critical role of creating a physical boundary between the delicately balanced internal environment
of the cell and the often dangerous, chaotic conditions that
can exist outside the cell.
Finally, the cell membrane allows the cell itself to be
flexible and elastic. This allows the cells of animals and
most protozoans to easily change shape, and this is a great
help in creating an ease of motion that would be impossible
in a rigid organism.
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CONCLUSION
In this program, we have been introduced to the world of
cells. We have taken a brief look at their most important
structures and have learned their primary functions.
Yet, many of the biochemical reactions which underlie
those cellular functions are complex and not understood
by even the most highly trained scientists using the most
modern and sophisticated equipment.
Still, cell research has shown that all of the structures in
normal healthy living cells work harmoniously together
performing whatever needs to be done to perpetuate life.
Every second of every day, an individual cell performs
thousands of incredibly diverse and yet interrelated jobs.
And at all times, the internal structures of the cell are in
continuous motion--throbbing, moving, breaking apart,
coming together, stretching and contracting.
In the final analysis, cells can be thought of as marvelous
and complex miniature factories whose final product is
none other than life itself.
VIDEO QUIZ
1. True or False: Cytoplasm is the part of a cell's protoplasm found inside of the nucleus. A. False
2. True or False: The nucleus contains very little of the
cell's DNA. A. False
3. True or False: Genes are made up of DNA. A. True
4. These organelles called __________ are where proteins
are assembled. A. ribosomes
5. These organelles called __________ are thought of as the
"powerhouses of the cell." A. mitochondria
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6. Layers of identical cells found in most multicellular
organisms are called __________. A. tissues
7. The outer, non-living, layer of plant cells is called the
_______ ________. A. cell wall
8. Both animal and plant cells contain a thin, flexible layer
called the __________ __________ that is very important in
controlling what enters and leaves the cell. A. cell membrane (sometimes called the plasma membrane)
9. True or False: Proteins can be packaged for export
outside of the cell by a special structure called the Golgi
apparatus. A. True
10.Photosynthesis is carried out in these organelles called
__________. A. chloroplasts
END
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Name _______________________________
CELLS: THE BASIC UNITS OF LIFE
VOCABULARY LIST
Cell The smallest biological unit capable of carrying out all of the fundamental activities of life. The basic unit of structure and function of any living thing.
Cell Membrane The thin, flexible layer that surrounds a cell and which controls all that enters and leaves the cell.
Cell Wall In plant and bacterial cells, the outermost non-living cellulose layer that surrounds the entire cell, including the
cell membrane.
Centriole In animal cells, a structure outside the nucleus that organizes the spindle fibers during cell reproduction.
Centrosome Another name for the centriole.
Chlorophyll A green pigment found in the chloroplasts of plant cells that is essential for photosynthesis.
Chloroplasts The chlorophyll-containing organelles found in the cytoplasm of plant and algae cells.
Chromatin The coils of DNA and protein that condense to form chromosomes. Chromatin can be thought of as chromosomes with no distinct shape.
Chromosomes Distinct wormlike cell structures formed from chromatin during cell reproduction.
Contractile Vacuoles Large sacs found in the cells of certain protozoans that remove the water that has accumulated
inside the cell by pumping it to the outside of the cell.
Cilia Hairlike structures found on the outside of certain cells. The protozoans called ciliates use cilia to propel themselves through the water in which they live.
Cytoplasm That part of a cell's protoplasm that lies outside of its nucleus.
Deoxyribonucleic Acid (DNA) A large and very complex biochemical that stores the information needed to construct
proteins and that carries the genetic information about an organism.
DNA The abbreviation for deoxyribonucleic acid.
Endoplasmic Reticulum The intricate system of tubes leading from the nuclear membrane into the cytoplasm that is
involved in transporting proteins.
Enzyme A special class of proteins that control the rates of biochemical reactions.
Flagellum A long, whiplike cell structure used to propel sperm cells as well as the cells of the protozoans known as
flagellates.
Food Vacuoles The sacs where food particles are digested that are found in the cytoplasm of protozoan cells.
Gene The basic unit of heredity, made up of a specific region on a DNA molecule. Also a specific region of a DNA
molecule that holds the code for one specific protein.
Golgi Apparatus A subcellular organelle involved in packaging proteins for export from the cell.
(Continued on Blackline Master 2)
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CELLS: THE BASIC UNITS OF LIFE
VOCABULARY LIST
(Continued from Blackline Master 1)
Lysosomes In animal cells, the organelles where large food molecules are broken down into smaller, more useful, food
molecules.
Microtubules Tiny tubules inside the cell that form the cell's internal "cytoskeleton" and that help rearrange structures
inside the cell.
Mitochondria The organelles known as the "power houses of the cell" where the stored energy of food is made available
for use within the cell.
Multicellular A word used to describe organisms made up of many cells.
Nuclear Membrane A layer inside the cell that surrounds the nucleus and contains many tiny pores.
Nucleus A large structure within the cell that contains chromatin, the nucleolus, and is surrounded by a nuclear membrane.
Nucleolus The "little nucleus" found inside the nucleus which is made up of RNA and protein.
Organelle A tiny cell structure; a miniature organ. Ribosomes, mitochondria, and chloroplasts are all organelles.
Phagocytosis A method by which cells take in food by surrounding and engulfing it. Amebae and white blood cells take
in food by this method.
Photosynthesis The process by which plant cells make food and oxygen from water, carbon dioxide, and sunlight.
Plasma Membrane Another name for the cell membrane.
Plasmalemma Another name for the cell membrane.
Protein A class of biochemicals made up of amino acids that can be important in building and repairing cells or in
controlling chemical reactions inside the cell.
Protoplasm All the living materials inside a cell.
Ribonucleic Acid (RNA) A class of nucleic acids that can be used either in reading the genetic information on the DNA
or in guiding the process of making proteins.
Ribosomes The organelles where proteins are assembled.
RNA The abbreviation for ribonucleic acid.
Spindle Fibers Microtubules visible during cell division that are involved in separating chromosomes into two separate
identical groups.
Tissue Layers of closely related cells that work together to perform a specific function, such as muscle tissue, liver tissue,
nervous tissue, etc.
Unicellular An organism composed of just one cell.
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CELLS: THE BASIC UNITS OF LIFE
A TYPICAL ANIMAL CELL
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3a
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Name _______________________________
CELLS: THE BASIC UNITS OF LIFE
CLOSE-UP OF A TYPICAL ANIMAL CELL
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4
CELLS: THE BASIC UNITS OF LIFE
A TYPICAL PLANT CELL
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12
CELLS: THE BASIC UNITS OF LIFE
CLOSE-UP OF A TYPICAL PLANT CELL
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Name _______________________________
CELLS: THE BASIC UNITS OF LIFE
PATHWAYS WITHIN THE CELL
1. Chromatin contains DNA instructions
for proteins.
4. Enzyme proteins digest food chemicals
in the lysosomes.
2. Proteins are made on ribosomes.
5. Food chemicals are converted into energy
in the mitochondria.
3. Proteins and protein information
travel in the Endoplasmic Reticulum.
©1994 Chariot Productions
6. Cell products, such as some proteins, are
packaged for export outside the cell
by the Golgi Apparatus.
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CELLS: THE BASIC UNITS OF LIFE
CROSSWORD PUZZLE
2
1
3
4
8
6
7
5
9
10
11
12
DOWN
1. The basic unit of structure and function of any living thing.
2. The powerhouses of the cell.
3. All the protoplasm outside the nucleus.
4. Layers of closely-related cells that work together to perform
specific tasks.
5. The outer, non-living, layer of plant cells.
6. The organelles where proteins are assembled.
7. The thin, flexible layer that surrounds animal cells.
©1994 Chariot Productions
ACROSS
1. Wormlike cell structures derived from chromatin during cell
reproduction.
3. A structure in animal cells that organizes the spindle fibers
during cell reproduction.
5. The organelles of plants where photosynthesis occurs.
6. The abbreviation for ribonucleic acid.
8. A threadlike material of DNA and protein found in the nuclei of
non-dividing cells.
9. The organelles in animal cells where large molecules are broken
down into smaller molecules.
10. The abbreviation for deoxyribonucleic acid.
11. The cytoplasm's intricate network of tiny tubes is called the
__________ reticulum.
12. The __________ apparatus is used to export certain proteins to
the outside of the cell.
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CELLS: THE BASIC UNITS OF LIFE
INTERACTIVE VIDEO QUIZ
1. True or False: Cytoplasm is the part of a cell's protoplasm found inside of the nucleus.
2. True or False: The nucleus contains very little of the cell's DNA.
3. True or False: Genes are made up of DNA.
4. These organelles called _________________ are where proteins are assembled.
5. These organelles called _________________ are thought of as the "powerhouses of the cell."
6. Layers of identical cells found in most multicellular organisms are called_______ __________.
7. The outer, non-living, layer of plant cells is called the _________
__________.
8. Both animal and plant cells contain a thin, flexible layer called the __________ _____________
that is very important in controlling what enters and leaves the cell.
9. True or False: Proteins can be packaged for export outside the cell by a special structure called
the Golgi apparatus.
10.Photosynthesis is carried out in these organelles called _________________.
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CELLS: THE BASIC UNITS OF LIFE
LESSON QUIZ, PART 1
VOCALULARY WORD MATCH
Place the alpha character from the list on the right on the line preceding the matching word on the left.
___ Cell
A. Distinct wormlike cell structures formed from chromatin during cell reproduction.
___ Cell Wall
B. A class of biochemicals made up of amino acids that can be important in building and
repairing cells or in controlling chemical reactions inside the cell.
___ Chromosomes
___ Deoxyribonucleic Acid
(DNA)
___ Enzyme
___ Gene
C. A large structure within the cell that contains chromatin, the nucleolus, and is surrounded by a nuclear membrane.
D. The basic unit of heredity, made up of a specific region on a DNA molecule. Also a
specific region of a DNA molecule that holds the code for one specific protein.
E. The process by which plant cells make food and oxygen from water, carbon dioxide,
and sunlight.
___ Nucleus
F. A special class of proteins that control chemical reactions.
___ Photosynthesis
___ Protein
G. A large and very complex biochemical that stores the information needed to construct
proteins and that carries the genetic information about an organism.
___ Ribonucleic Acid
(RNA)
H. A class of nucleic acids that can be used either in reading the genetic information
on the DNA or in guiding the process of making proteins.
I. The basic unit of structure and function of any living thing. The smallest biological unit
capable of carrying out all the fundamental activities of life.
J. In plant and bacterial cells, the outermost non-living cellulous layer that surrounds the
entire cell, including the cell membrane.
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Name _______________________________
CELLS: THE BASIC UNITS OF LIFE
LESSON QUIZ, PART 2
TRUE OR FALSE - Place a T for True and an F for False in the box preceding each statement.
1. All bacterial cells are dangerous to humans.
2. Plants and animals both have tissue.
3. Scientists no longer accept the basic principles of the early 19th century "Cell Theory"
of Theodore Schwann and M. J. Schlieden.
4. The internal structures of the cell are at rest at times.
5. Even highly trained scientists using the most modern and sophisticated equipment do
not understand many of the complex biochemical reactions which underlie cellular
functions.
FILL IN THE BLANK
1. Living things are all made up of _________.
2. All living things have 7 characteristics. List at least five of them below.
3. Many of nature's simplest creatures are nothing more than single, independently living cells and
are called ______________ organisms.
4. In larger, more biologically advanced creatures called ________________, many different kinds of
cells are joined to perform specialized tasks.
5. Cells can be thought of as marvelous and complex miniature factories whose final product is
_________.
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10
CELLS: THE BASIC UNITS OF LIFE
LESSON QUIZ, PART 3
ESSAY QUESTIONS. Use the back of this sheet or another sheet of paper if necessary.
1. Explain how, nearly four hundred years ago, cells came to be named.
2. Briefly explain Theodore Schwann's and M. J. Schlieden's "Cell Theory."
3. Certain differences exist between the structure of animal and plant cells. Write a few paragraphs
that compare and contrast animal and plant cells.
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