CELLebrate Life:
Cells, the Building
Blocks of Life
2012-2013
CELLabrate Life
Cells: The Building Blocks Of Life
I.
Lab 1: Meeting the Compound
II.
Lab 2: Seeking Hidden Worlds
III.
Cells: I’m Sold on Cells (Classroom Copy of Article)
IV.
Reading: P. 2 – 23 with Reading Road Map
V.
Bill Nye Video: “Cells” with Worksheet
VI.
Important Cell Structures and Organelles Worksheet
VII.
Organelle Analogies
VIII. Cell Model Project or Parts Wanted Activity
IX.
Lab 3: Cells Alive
X.
Lab 4: Comparing Plant and Animal Cells
XI.
Reading: P. 34-36
XII. “Building a Eukaryotic Cell” Diagram
XIII. Lab 5: Cell Membranes and Permeability
XIV.
Vocabulary Review Worksheet: “A Cell Crossword Puzzle”
2
Cells
Enduring Understandings:
1. The process of identifying and classifying organisms and nonliving
items is based on a set of characteristics that allows them to be placed
into categories.
2. All living organisms have structures and systems that are needed for
survival.
3. The cell is the basic unit of life having specialized parts with specific
tasks.
4. There are different levels of organization within organisms and
ecosystems.
Essential Questions:
1. How are unicellular and multicellular organisms alike and different?
2. Identify the differences and similarities between plant and animal cells.
3. How does an organism’s form help aid in its function to survive?
4. Explain how organelles carry out a specific job for the cell.
5. Describe the levels of organization in living things from cells to
ecosystems.
Critical Vocabulary:
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
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Cell
Tissue
Organism
Unicellular
Multicellular
Nucleus
3
DNA
Organism
Population
Community
Organelles
Ecosystem
Lab 1: Meeting the Compound
Introduction: One of the most important tools of a life scientist is the microscope. The
development of the microscope has made possible the identification of
thousands of different organisms and parts of organisms that are invisible
to the unaided eye. The microscope you will be using is a compound
microscope. That is, it contains more than one lens. The lenses are the
parts of the microscope that are responsible for magnifying the object
being viewed.
In this investigation, you will learn how to correctly handle a microscope.
The compound microscope that you are using may not look exactly like
the one pictured in this investigation. However, the parts of most
compound microscopes are the same and have the same names.
Materials:
Microscope
Procedure:
Part A—Learning the Terms
1. With a partner, study the picture of the compound microscope
and its labeled parts. Use this picture as a guide to identify the
parts of the microscope that is at your table.
2. After several minutes, your teacher will tell you to cover the
picture and try to identify as many of the different parts of the
microscope at your table as you can.
Name: ____________________________________
Period: ________
Identifying the Parts of a ___________________ Microscope
Directions: Write the correct name for each part in its box.
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Name: ___________________________
Period: _______
Part B—Understanding Each Part
The following is a description of the parts found in a compound microscope.
Read the description carefully and locate it on your microscope and the
picture. Place the correct term or terms in the appropriate blanks below.
1. The _______________ _______________ is a hollow cylinder which
allows light to pass upward and through to the eyepiece. The upper
portion of the tube contains the eyepiece and may contain one or more
other lenses.
2. _______________ is located directly above the low-, mid- and high-power
objective lenses. It can be rotated to change magnification. The revolving
nosepiece contains two or more small cylinders having magnifying lenses
called _______________.
3. The _______________ _______________ _______________, often colorcoded red, contains a series of lenses which magnify an amount indicated
on the side of the objective. A 4x magnification is usually found on this
objective. Multiply the objective magnification by the eyepiece
magnification to determine the low-power (L.P.) magnification of your
microscope. _______________
4. The _______________ _______________ _______________, often colorcoded yellow, contains stronger lenses, giving greater magnification. A
10x magnification is usually found on this objective. Multiply the
objective magnification by the eyepiece magnification to determine the
mid-power (M.P.) magnification of your microscope. _______________
5. The _______________ _______________ _______________, often is
color-coded blue contains the highest power lenses of all. Again multiply
the eyepiece times the objective to obtain the power of magnification.
_______________
6. A pair of _______________ _______________ are located on the stage
and hold the slide in place.
7. The _______________ _______________ beneath the stage has many
small openings of various sizes. By turning this, you can increase or
decrease the amount of light entering through the stage opening.
8. The ________________ is transmitted through your specimen while
sitting on the stage.
6
9. The _______________ is the part of the microscope that you look through
to view an object placed on the stage. The eyepiece contains the ocular
lens and usually has a magnification power of 10x. This means that the
lens enables you to see the object ten times larger than it actually is. What
magnification is marked on the top of the eyepiece of your microscope?
_______________
10. The _______________ supports the body tube. It is also used to carry the
microscope, while holding the bottom with your other hand, and carry it
upright to avoid dropping the eyepiece or moving the lenses.
11. The _______________ is a platform upon which materials are placed for
observation. An opening in the center permits light to pass from below
through the object to be studied.
12. The _______________ _______________ _______________ is a large
knob that moves the stage up and down to bring the object into view. It is
usually located on the side of the arm. CAUTION: Do not use this when
focusing the high-power objective lens. This could break the slide.
13. The _______________ _______________ _______________ is the
smaller knob that is usually located below the coarse focus knob. It is
used to bring objects into clear, sharp focus. Turning this knob, raises and
lowers the stage so slightly that it can hardly be noticed. It is used when
focusing with the high-power objective. Never use this knob for large
adjustments. If the object is properly focused with the coarse focus knob,
then it should take only one fourth of a turn of this knob to bring the object
into a sharp focus.
14. The _______________ is a heavy rectangular shaped section of the
microscope that contains a light or mirror. This part of the microscope is
designed to be heavy to hold the microscope in place.
7
Part C: Important Rules To Follow For Better Success With The Microscope
1. When transporting the microscope, always carry it by the arm with one hand,
while using the other hand to support the base. Always keep the microscope
in an upright position or the lenses may slip out of position and fall to the
floor. When setting it down on the laboratory table, set it down gently or you
may jar some of the lenses out of position.
2. If the lenses in the microscope need cleaning, clean them only with lens paper
which is provided by your teacher. Other materials may permanently scratch
the lenses.
3. If you wear glasses, it is not usually necessary to use them while looking
through the microscope. The focusing of the instrument’s lens system
automatically corrects itself for your vision. However, it does not correct for
astigmatism, and you should wear your glasses in this case. Be careful that
you do not scratch the lens on your glasses on the metal rim around the
eyepiece.
4. Always focus the stage downward when the eye is at the eyepiece. If you
focus upward, there is danger of ruining the lens or the object being studied.
5. When rotating objectives, always be sure that they do not touch the stage or
slide. It is best to look at the slide from the side, while moving the objective.
Forgetting this has ruined many good slides and a large number of lenses.
6. Keep both eyes open all of the time. This may seem difficult at first, but it
will become easier with practice, and will give better viewing. It also helps
when you are making drawings, because it doesn’t cause you to refocus your
eyes from the microscope to the paper.
7. Always find your object on LOW-POWER First. Center the object, and then
rotate carefully to the mid-power objective. Do this if the details cannot be
seen on the low-power setting. When you have determined if you still need
more power, turn the objective to high-power. REMEMBER to use only the
FINE FOCUS KNOB when at high-power.
8. When putting the microscope away for the day, the microscope should be
positioned on the low-power objective lens 4x. The stage should be
positioned all the way up. Make sure that you do this in the order listed.
Replace the cover to guard from getting dusty.
9. Clean the glass slide with soap and water. Rinse it thoroughly with the water
and wipe dry while holding the slide on the edges. In a like manner, clean and
dry the cover slip. Remember to be careful with cleaning the slips as they are
very fragile and easily broken or distorted.
8
Name: ________________________________
Period: _______
Questions:
1. What may happen if the microscope is left uncovered at the end of the class
period?
_______________________________________________________________
2. When storing the microscope, which objective should be positioned above the
stage?
_______________________________________________________________
3. Why should a microscope be carried in an upright position?
_______________________________________________________________
4. When focusing the microscope, in which direction should the stage move?
_______________________________________________________________
5. Why should both eyes be kept open when using the microscope?
_______________________________________________________________
6. What should be used to clean the microscope lenses?
_______________________________________________________________
7. If you wear glasses normally, do you need to wear them when using the
microscope?
_______________________________________________________________
8. Explain the reason for the answer you gave to question 7.
_______________________________________________________________
9. Which objective is used first when viewing a slide?
_______________________________________________________________
9
Lab 2: Seeking Hidden Worlds
Introduction: All around you are hidden worlds. Flat surfaces that look clean to your
eye may contain startling differences when viewed under magnification.
Drops of water may be filled with strange, living organisms. Your key to
these worlds is your microscope. You must learn to care for and use your
microscope properly.
Materials:
compound microscope
Glass slide
Forceps
cover slip
scissors
newspaper print
Procedure:
Skill in using the microscope and in preparing materials for examination
can be developed only by following all steps in the procedure. Perform
each step in the given order.
Part A: Getting The Compound Ready
1. Place the microscope with the back of the base about 2 –3 inches from the
edge of your table.
2. If your teacher directs you to, wipe the top lens of the eyepiece, the lens of
each objective, and the mirror with the lens paper.
3. Make sure that the low-power objective is in line with the body tube. When it
is in the proper position, it will click.
4. Turn the disk diaphragm to the largest opening so that the greatest amount of
light can be admitted.
5. Put your eye to the eyepiece and you will notice a bright uniform circle of
light without any shadows. This is the field. You will note a black line is
visible in the field. The line is controlled by rotating the eyepiece. This is
used as a pointer.
10
Name: _________________________
Period: _____
6. Predict the diameter of the field when set at low power.
My prediction in mm: _______________
7. Obtain a flat, clear 15cm ruler. Lay it flat on the stage. Carefully measure the
actual field that you view using the low power objective.
My actual measurement: _______________
8. Repeat the measurement but carefully rotate the mid-power lens into position.
My actual measurement: _______________
9. Again, repeat the procedure, but carefully rotate the high-power lens into
position.
My actual measurement: _______________
10. Put a dot in the center of the blank space below.
11. Draw a circle around the dot that has the diameter you recorded in number 7.
12. Draw a circle around the dot that has the diameter you recorded in number 8.
13. Draw a circle around the dot that has the diameter you recorded in number 9.
14. Why would it be very important to have a specimen centered before moving
to high power?
_______________________________________________________________
_______________________________________________________________
11
Part B: Looking at a Prepared Slide
1. Place the scope in the beginning position. (low power objective down, stage
in the full upright position)
2. Place a prepared slide on the stage with the specimen centered above the hole
in the stage.
3. Place the stage clips on the slide.
4. While looking through the eyepiece, turn the coarse focus knob causing the
stage to lower slowly.
5. Continue until the specimen comes into view.
6. Use the fine adjustment knob to bring the specimen clearly into sharp focus.
7. Look at your objective lenses from the side. Rotate the mid-power objective
into the down position. Make sure that it locks into position. Now look
through the eyepiece again. If focusing is needed, use only the fine focus
knob.
8. While looking from the side again, turn the high power lens to the viewing
position.
9. Use ONLY the fine focus knob to bring the specimen into sharp focus.
10. Read set microscope to low power with the stage all the way up. Remove
slide.
11. Now exchange your slide and repeat steps 1 – 10.
12. I was able to view slides that contained the following:
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
12
Part C: Making a Wet Mount
1. Clean a blank slide if needed with soap, water, and paper towel and make sure
you have a cover slip.
2. Put 1 drop of water in the center of the slide. The water is a mounting
medium and is necessary to obtain a clear image of the material to be studied.
3. From the smallest print in the newspaper (usually obtained from the stock
exchange page), get a word that contains the letter d. It should NOT be a
capital letter. Using the forceps to hold the letter d, cut off the rest of the
letters. Put the letter on the drop of water so that you can read it face up.
4. Touch the cover slip to the edge of the drop of water. Gently lower the cover
slip onto the drop of water as shown in the picture below.
5. Have the stage set in the lowest position. Then put the mounted slide on the
stage as you did previously with the prepared slides. Clip it into place and
move it with your thumbs and forefingers until the letter is in the center of the
stage opening. Make sure it is in the position where you can read it face up.
6. Once you have the slide in place, move the nosepiece to the lowest power
objective and, using the coarse focus knob, move the stage as high as it will
go.
13
7. Put your eye to the eyepiece and, as you watch the field, turn the coarse focus
knob slowly. This will cause the stage to lower. Watch for the material to
appear in the field. Go slowly so that you will not miss when the object
comes into focus.
8. Bring the letter into sharp focus with the fine focus knob. As you examine the
letter, turn the fine focus knob slowly back and forth. This should not be
more than half a turn. This will shift the focus to bring out details at different
levels of the object. Remember that details can also be brought out more
clearly by rotating the disk diaphragm. Try at each light level to find the best
for your viewing.
9. Compare the position of the letter as it is mounted on the slide with its actual
appearance under the microscope.
Remember when you placed the letter on the slide and put the slide into
position, the letter was facing right-side up towards you?
How has the microscope changed the apparent position of the letter as you are
viewing it now?
_______________________________________________________________
_______________________________________________________________
10. While you are looking through the eyepiece on low-power, push the slide
away from you (up on the stage) using your thumbs. Which direction does the
letter move in the field?
_______________________________________________________________
11. Push the slide to the left. Which direction did the letter move in the field this
time?
_____________________________________________________________
12. Carefully draw what you see in the microscope. Remember the circle for the
drawing is referred to as a field.
Title
_______________
Power _______________
Date
_______________
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13. Now move the letter to the exact center of the field, check for sharp focus, and
turn the mid-power objective into position. The letter should now be visible
under the lens. Correct the sharpness of focus with the fine focus knob. You
should also try rotating the disk diaphragm. This will allow for variations in
the light being transmitted. Describe what you see.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
14. Now draw what you see on mid-power.
Title
_______________
Power _______________
Date
_______________
15. Now repeat the procedure used, but this time focus the letter using highpower.
Title
_______________
Power _______________
Date
_______________
15
Part D: It’s Not Always Black and White
1. Create a slide using a small (about .5 cm) square of colored paper. (Do not
use water for mounting, just keep it dry.)
2. Place the slide on the microscope stage and observe with the low-power
objective.
3. Use colored pencils to draw what you see in the circle below.
Title
_______________
Power _______________
Date
_______________
4. When you have drawn your colored picture, carefully remove your cover slip
from the slide, take off the colored newsprint and tape it here.
Questions:
1. How is viewing the newspaper different under the microscope, as compared to
looking at it with your own eyes?
__________________________________________________________________
__________________________________________________________________
2. The newsprint appears to use solid color, but what do you notice about the color
when you look at it under the microscope?
__________________________________________________________________
__________________________________________________________________
16
Part E: Looking at Onion Cells
1. Take a small slice of onion.
2. Break the piece in half, but make sure that the thin outer layer of skin is still
holding the two pieces of onion together.
3. Gently pull each piece of onion away from the skin using forceps.
4. Place the skin on a clean slide and smooth it out as much as possible.
5. Put a small drop of iodine on the onion to stain it for better viewing. (You will
notice that the stain will darken the cell walls and the nucleus in each cell.)
6. Add cover slip!
7. Draw and color what you observed under LOW power. Label the cell wall,
cytoplasm, one cell, and the nucleus.
Title
_______________
Power _______________
Date
_______________
8. Draw and color the onion cells as you observe it under HIGH power. Label the
cell wall, cytoplasm, one cell, and the nucleus.
Title
_______________
Power _______________
Date
_______________
17
Part F: Looking at Cheek Cells
Materials:
Flat Toothpick
Cheek Cells
Methylene Blue Stain
Microscope Slide
Cover Slip
Compound Microscope
Procedure:
1. Scrape the inside of your cheek with the wide end of a flat toothpick.
2. Smear the cheek cells (that you have just collected) onto a microscope
slide. You won’t be able to see them with your unaided eye.
3. Put one drop of Methylene Blue stain onto the slide.
4. Add cover slip!
5. Draw the cheek cells as you observe them under Low power. Label
the cell membrane, one cell, cytoplasm, and the nucleus.
Title
_______________
Power _______________
Date
_______________
6. Draw the cheek cells as you observe them under HIGH power. Label
the cell membrane, one cell, cytoplasm, and the nucleus.
Title
_______________
Power _______________
Date
_______________
Estimate the length of an average onion cell: ___________________
(Using what you already learned about the diameter of the field)
18
Part G: Looking at Blood Cells
Materials:
Compound Microscope
Prepared Human Blood Smear
Procedure:
1. Diagram the blood sample on LOW power.
Title
_______________
Power _______________
Date
_______________
2. Diagram the blood sample on High power.
Title
_______________
Power _______________
Date
_______________
3. Label ONE red blood cell and ONE white blood cell in the high power
diagram. Also label the cell membrane and cytoplasm.
19
Part H: Goldfish - See the Blood Flow (optional)
Procedure:
1. Your teacher may show a video clip, so that you may view flowing blood in a
living creature.
Part I: Cork Cells - A View From The Past
When you begin reading Chapter 1 in your Cells textbook, you will learn that a
Scientist by the name of Robert Hooke wrote of tiny boxes that reminded him of
honeycomb. Hooke called these tiny boxes “cells.”
Procedure:
1. Obtain a prepared cork cell slide from the supply area.
2. Diagram what you see on low power:
Title
_______________
Power _______________
Date
_______________
20
Part J: Leeuwenhoek’s Invisible World
Leeuwenhoek is another scientist who made important discoveries in microbiology.
Using a handmade microscope, he often saw tiny creatures which he called “tierkin” or
“beasties.”
Get a sample of pond water from the supply area. Make a wet-mount as you have
learned. You need not add additional water. Locate and draw (as carefully as
possible) 5 different kinds of life.
Try to identify this life. Use the resources available. You may also wish to make
additional slides, but make sure that you include a drawing and identification for each
extra slide.
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
21
Name: _____________________________
Reading Guide for:
“Cells – I'm Sold on Cells”
The article provides you with analogies to help you better understand the functions of
various cell structures and organelles. As you read the article, look for the analogies and
complete the chart below.
Cell Structure
or Organelle
Analogy
How so? In what way is this analogy correct?
The human body is A house is made up of rooms just like your body is made
analogous to a house. up of cells.
Human body
Cells are analogous
to the rooms in a
house.
Cells
Cell wall and
cell membrane
There are different types of rooms in a house just like there
are different types of cells. Each type has a special job – it's
used for different jobs. The different cells have many
features in common (windows, doors, etc.) just like cells
have many features in common (outside covering,
cytoplasm inside, etc.).
The cell wall and cell
membrane are
analogous to.......
The nucleus is
analogous to......
Nucleus
22
Cell Structure
or Organelle
Analogy
How so? In what way is this analogy correct?
Mitochondria
Golgi body
Lysosomes
Cytoplasm
Different
kinds of cells
23
Name_________________________
Period: _____
Reading Road Map
Cells Unit
Directions: Use this reading road map to guide you through the cells unit. Make sure to
complete each mission.
Location
Organization of
Life-Pg. 4.
Speed
Read
Mission
1. What is a cell?
2. What do cells make up?
Starting Out
Small – Pg. 4
Read
3. Name 2 other types of cells.
a.
b.
Cells Working in
Teams – Pg. 5
Read
4. Define Tissue.
Teams Working
Together –Pg. 5
Organ Systems –
Pg. 6
Read
5. Define organ.
Read
6. Define organ system?
Organisms – Pg.
7
Read
7. What is the difference between multicellular
and unicellular?
Refer to Pg. 7,
Figure 7
Speeding
Ticket!
The Cell Theory
–Pg 10.
Slow Down
8. Describe the level of cellular organization
from cell to organism. (Hint: use words and
arrows!)
9. What are the three parts of the cell theory?
a.________________________________________
b. _______________________________________
c. _______________________________________
24
Cell Membrane –
Pg. 16.
Read
10. What is the cell membrane’s job?
Cell Wall – Pg.
17.
Read
11. Do animal cells have cell walls?
12. Why or why not?
Cell Library –
Pg. 17.
Slow
13. Why can the nucleus be called the control
center of the cell?
Protein
Factories-Pg. 18.
Read
14. Why do cells have ribosomes?
The Cell’s
Delivery System
–Pg. 18.
Read
15. What is the function (job) of the
endoplasmic reticulum?
The Cell’s Power
Plant – Pg. 19.
Slow
16. What produces a plant cell’s energy?
17. What produces an animal cell’s energy?
The Cell’s
Packaging
Center –Pg. 20.
Vacuoles-Pg.21
Lysosomes – Pg.
22
Table –
Organelles and
their functions –
Pg. 22
Plant or Animal
– Pg. 23
Read
18. What is the function of the golgi complex?
Skim
19. What is a vacuole?
Skim
20. What is a lysosome?
Scenic
Read
This table is very useful for remembering what
each organelle is responsible for in a cell!
No answer needed!
21.List 3 differences between plant and animal
cells.
a.________________________________________
b. _______________________________________
c. _______________________________________
25
Name: ________________________
Period: _____
IMPORTANT CELL STRUCTURES & ORGANELLES
Cell Type
Plant
Animal
Structure /
Organelle
Job / Duties / Responsibilities
 keeps the __________________________ inside the cell
 allows ___________________________ into the cell
cell
membrane
 allows _____________________ products out of the cell
 ________________________ with things outside the cell
 helps __________________________________________
 provides ______________________________ to the cell
membrane
cell wall
 provides ______________________________ to the cell
membrane
 helps __________________________________________
 stores the ________________
nucleus
_______________ is very important because it carries all the
_________________ information about how to make you!!!!!
 For this reason, we sometimes say the nucleus is like the
cell’s ____________________________
 the _____________________ ______________________
of all cells
ribosomes
 these are considered the __________________________
factories
 makes _____________________________ to be used inside
and outside the cell
endoplasmic  ________________________ _______________________
reticulum
________________________ that could damage the cell
(ER)
 allows substances to ______________________ from one
place to another through its ______________________
 considered the cell’s _______________________
Cell Type
Plant
Animal
Structure /
Organelle
Job / Duties / Responsibilities
 most ____________________ is produced here
mitochondria
__________________ is important because the cell uses it
for ______________________
 considered the cell’s _______________ ____________

chloroplasts
use the _________________ energy to make
______________________
the ____________________ is used by the cell’s
_____________________ to make _________________, which is
used to provide _________________ to the cell
 also considered the cell’s _______________ _______________
 ________________________ and
________________________ materials inside and out
golgi complex
of the cell
 considered the cell’s ______________________
_____________________
 compartments that are used to __________________
materials
vesicles
 considered to be a _____________________
_____________________
vacuole
 stores __________________ and other
____________________
 when full, helps provide ________________ for the cell
 also considered the cell’s ____________ ____________
lysosomes
 special _____________________ that contain
__________________________
 __________________________ worn out or damaged
organelles
 gets rid of _____________________ materials
 protects the cell from foreign _____________________
 considered packages of ______________________
27
Name(s): ______________________________________
Period: ______
Organelle Analogies
Directions: Next to each organelle, draw what it is analogous (similar) to in normal, everyday life, then
write a complete sentence stating how the two are similar. You may not use the same analogies that are in the
textbook!!!
Organelle
Drawing
Sentence
Cell
Membrane
Cell Wall
Nucleus
Ribosomes
Mitochondria
28
Organelle
Drawing
Sentence
Chloroplasts
Endoplasmic
Reticulum
Golgi
Complex
Vesicles
Vacuoles
Lysosomes
29
Lab 3: Cells Alive
Introduction: You have probably used a microscope to look at single-celled organisms.
They can be found in pond water. In the following exercise, you will look
at Protococcus—algae that form a greenish stain on tree trunks, wooden
fences, flowerpots, and buildings.
Men
Materials:
Protococcus (or other algae)
water
Microscope
microscope slide and coverslip
eyedropper
Procedure:
1. Locate some Protococcus. Scrape a small sample into a container.
Bring the sample to the classroom, and make a wet mount of it as directed
by your teacher. If you can’t find Protococcus outdoors, look for algae on
the glass in an aquarium. Such algae may not be Protococcus, but they
will be a very good substitute.
2. Set the microscope on low power to examine the algae. In the space
provided below, draw the cells that you see.
Title
__________________
Power __________________
Date
__________________
3. Switch to high power to examine a single cell. Draw the single cell that
you see.
Title
__________________
Power __________________
Date
__________________
28
4. You will probably notice that each cell contains several chloroplasts.
Label a chloroplast on your drawing. What is the function of the
chloroplast?
____________________________________________________________
____________________________________________________________
____________________________________________________________
5. Another structure that should be clearly visible in all the algae cells is
the nucleus. Find the nucleus in one of your cells, and label it on your
drawing. What is the function of the nucleus?
____________________________________________________________
____________________________________________________________
____________________________________________________________
6. What does the cytoplasm look like? Describe any movement you see
inside the cells.
____________________________________________________________
____________________________________________________________
____________________________________________________________
Analysis:
7. Are Protococcus single-celled organisms or multicellular organisms?
Why or why not?
____________________________________________________________
____________________________________________________________
____________________________________________________________
8. How are Protococcus different from amoebas?
____________________________________________________________
____________________________________________________________
____________________________________________________________
Sample answer: Both cells contained an endoplasmic re
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Lab 4: Comparing Plant and Animal Cells
Introduction: All living things are made up of cells. Cells are the basic unit of structure
and function of living things. There are many types of cells. Whether
they are plant or animal cells, most cells share certain characteristics. In
this investigation, you will compare the structures of a typical plant cell.
Materials:
Forceps
Medicine Dropper
Elodea Leaf
Water
Microscope
Microscope Slide
Cover Slip
Procedure:
Part A: Examining Plant Cells
1. Make a wet mount slide using an Elodea leaf.
2. Observe the cells of the leaf on high power. Draw and label what you
see.
3. Carefully clean and dry your slide and cover slip.
____________
____________
____________
4. Label cell wall, cytoplasm, and chloroplast in your drawing.
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Name: __________________________________
Period: ______
Lab 4: Comparing Plant and Animal Cells
Conclusions:
1. Describe the shape of the plant cells.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
2. How are plant and animal cells similar in structure?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3. How are plant and animal cells different in structure?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
4. Why didn’t you use a stains such as methylene blue or iodine used when
observing these cells under the microscope?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
5. How is the cell wall different from the cell membrane?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
6. Explain why you could not use an oak leaf in place of the plant we used in this
investigation.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
7. If you were given a slide containing living cells, how would you identify the
cells as either plant or animal?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Lab 5: Cell Membranes and Permeability
Introduction: Can all substances move in both directions through a cell membrane?
Why do some substances enter the cell through the cell membrane while
others do not? Sometimes you can use a model to answer questions like
theses. This investigation models a living cell, so that you can observe
changes that the cell membrane controls.
The cell membrane determines what diffuses into a cell. This
characteristic of a cell membrane in called permeability. Many cells are
semipermeable, which means that not all substances can pass though the
cell membrane. Also, the amount of a substance that diffuses through a
membrane is influenced by concentration and time.
In the investigation, you will model a cell membrane, and determine if the
membrane is permeable to certain substances.
Materials:
plastic bag
Twist tie
100-mL graduated cylinder
starch solution
200-mL beaker
glass marking pencil tubes
iodine solution
3 test tubes
test-tube rack
Procedure:
1. Write your name on a beaker with a glass-marking pencil. Then label
three test tubes as follows: (1) “Iodine BEFORE,” (2) “Iodine AFTER,”
and (3) “Starch.”
Figure 1
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2. Fill the beaker with 40 mL of iodine solution. CAUTION: Be careful
with the iodine solution. If you spill any on yourself, immediately rinse
the area with water and tell your teacher. The iodine solution
represents the environment outside the model cell.
3. Fill the test tube labeled “Iodine BEFORE” one-fourth full with iodine
solution, and then set it aside in a test tube rack.
4. Fill a plastic lunch bag with 40 mL of starch solution, and seal the bag
with a twist tie. Be careful not to spill starch onto the outside of the
bag. Record the color of the solution in Data Table 1, and then place
the bag into the solution in the beaker. The bag represents a cell.
5. Fill the “Starch” test tube about one-half full with starch solution,
record the color of the solution, and then place the test tube in the
beaker as shown in Figure 1. Let the beaker and its contents stand
overnight.
Day 2: Observations
6. The next day, remove the plastic bag and the test tube from the beaker.
Record the colors of the solutions in the plastic bag and the test tube in
the “Color AFTER” column in Data Table 1.
7. Pour iodine solution from the beaker into the test tube labeled “Iodine
AFTER” until the test tube has the same amount of solution as the test
tube labeled “Iodine BEFORE.”
8. Hold the two test tubes side by side, and look down though their
openings. Record the colors of the solutions in the last line of Data
Table 1.
Observations: Data Table 1
Solution
Color Before
Starch in model cell
Starch in test tube
Iodine in test tubes
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Color After
Name: ___________________________________
Period: _______
Cell Membranes and Permeability Conclusions:
1. What part of the cell does the plastic bag represent?
__________________________________________________________________
2. What was the purpose of placing a test tube containing starch solution in the
beaker of iodine?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
3. When starch mixes with iodine, the mixture turns blue. What can you infer about
the contents of the plastic bag?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
4. a. Did starch move out of the bag? Give a reason for your answer.
__________________________________________________________________
__________________________________________________________________
b. Did iodine move into the bag? Give a reason for your answer.
__________________________________________________________________
__________________________________________________________________
5. Based on your results, was the model cell membrane permeable of impermeable
to iodine? To starch?
__________________________________________________________________
__________________________________________________________________
Critical Thinking:
1. Cell membranes contain small holes or pores. Pore size may determine why some
chemicals can or cannot pass through a cell membrane. In you model, how might
the size of the membrane pores compare to the size of the iodine molecules?
Explain.
__________________________________________________________________
__________________________________________________________________
2. In your model, how might the size of the membrane pores compare to the size of
the starch molecules? Explain.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
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