Part 1 - Get a Lab Appointment and Install Software:
Set up an Account on the Scheduler (FIRST TIME USING NANSLO):
Find the email from your instructor with the URL (link) to sign up at the scheduler.
Set up your scheduling system account and schedule your lab appointment.
NOTE: You cannot make an appointment until two weeks prior to the start date of this lab assignment.
You can get your username and password from your email to schedule within this time frame.
Install the Citrix software: – go to http://receiver.citrix.com and click
download > accept > run > install (FIRST TIME USING NANSLO).
You only have to do this ONCE. Do NOT open it after installing. It will work automatically when you go
to your lab. (more info at
http://www.wiche.edu/info/nanslo/creative_science/Installing_Citrix_Receiver_Program.pdf)
Scheduling Additional Lab Appointments:
Get your scheduler account username and password from your email.
Go to the URL (link) given to you by your instructor and set up your appointment.
(more info at http://www.wiche.edu/nanslo/creative-science-solutions/students-scheduling-labs)
Changing Your Scheduled Lab Appointment:
Get your scheduler account username and password from your email. Go to http://scheduler.nanslo.org
and select the “I am a student” button. Log in to go to the student dashboard and modify your
appointment time. (more info at http://www.wiche.edu/nanslo/creative-science-solutions/studentsscheduling-labs)
Part 2 – Before Lab Day:
Read your lab experiment background and procedure below, pages 1-17.
Submit your completed Pre-Lab 1-3 Questions (pages 6-9) per your faculty’s instructions.
Watch the Microscope Control Panel Video Tutorial
http://www.wiche.edu/nanslo/lab-tutorials#microscope
Part 3 – Lab Day
Log in to your lab session – 2 options:
1)Retrieve your email from the scheduler with your appointment info or
2) Log in to the student dashboard and join your session by going to http://scheduler.nanslo.org
NOTE: You cannot log in to your session before the date and start time of your appointment. Use
Internet Explorer or Firefox.
Click on the yellow button on the bottom of the screen and follow the instructions to talk to your lab
partners and the lab tech.
Remote Lab Activity
SUBJECT SEMESTER: ____________
TITLE OF LAB: Introduction to Microscopy
Lab format: This lab is a remote lab activity.
Relationship to theory (if appropriate): In this lab you will learn the underlying principles
behind the histological study of tissues.
Instructions for Instructors: This protocol is written under an open source CC BY license. You
may use the procedure as is or modify as necessary for your class. Be sure to let your students
know if they should complete optional exercises in this lab procedure as lab technicians will not
know if you want your students to complete optional exercises.
Instructions for Students: Read the complete laboratory procedure before coming to lab.
Under the experimental sections, complete all pre-lab materials before logging on to the
remote lab. Complete data collection sections during your online period, and answer questions
in analysis sections after your online period. Your instructor will let you know if you are
required to complete any optional exercises in this lab.
Remote Resources: Primary – Microscope, Secondary – Introduction to Microscopy slide set.
CONTENTS FOR THIS NANSLO LAB ACTIVITY:
Learning Objectives...........................................................................................................
Background Information ..................................................................................................
Pre-lab Exercise 1: The Microscope ................................................................................
Pre-lab Exercise 2: Field of View and Depth of Field of a Compound Microscope ........
Pre-lab Exercise 3: Observation of Cells .........................................................................
Equipment ........................................................................................................................
Preparing for this NANSLO Lab Activity ...........................................................................
Experimental Procedure ..................................................................................................
Exercise 1: Operating a Compound Microscope .............................................................
Exercise 2: Field of View and Depth of Field of a Compound Microscope .....................
Exercise 3: Observation of Cells ......................................................................................
Summary Questions .........................................................................................................
Creative Commons Licensing ...........................................................................................
U.S. Department of Labor Information ............................................................................
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7-8
9
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9-10
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14-15
15-16
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17
LEARNING OBJECTIVES:
After completing this laboratory experiment, you should be able to do the following things:
1. Identify the parts of a compound microscope and operate it effectively.
2. Understand the basic differences between Dissecting, Compound, and Electron
microscopes.
3. Demonstrate the competency with the focus and operation of a microscope.
4. Use a microscope to capture images and turn them into figures.
BACKGROUND INFORMATION:
There are few things that have impacted the development of modern biology more than the
development of the microscope. Not only did the microscope open up a whole new world of
observation which directly led to the discovery of microorganisms, cells, and some cellular
components, but the microscope also affected the thought process and conduct of biological
research. As Sachs wrote in History of Botany, “ . . . the use of the magnifying glass brought an
advantage with it of a different kind - it taught those who use them to see scientifically and
exactly.” (Julius Sachs, 1890) Additionally, three Nobel prizes have been awarded for the
development of microscopes; the ultramicroscope won the award for chemistry in 1923, phase
contrast microscopy won the award for physics in 1953, and electron and force microscopes
won the award for physics in 1986 (Nobel Organization). Since the microscope is such an
important instrument not only for scientific observation but for the development of the field of
biology, we will spend a little time on the history and development of the instrument.
Humans have had at least a basic understanding of lenses for a long time. The existence of
“burning glasses” and “magnifying globs” (hollow glass spheres filled with water) can be traced
back almost 2000 years if not more (Singer, 1914). However, it was not until the 1300s, around
the time we begin to see lenses used for eye glasses, that magnification started to be used by
biologists (Singer, 1914). These earliest devices were single lens microscopes and had limited
magnification compared to modern scopes. The pinnacle of this type of microscope was
Leeuwenhoek’s discovery of “bacteria” in 1673 (Mazzarello, 1999).
During the 1600s, we begin to see the creation of the compound microscope which is a
microscope with multiple lenses. The earliest of these microscopes were very similar if not
identical to telescopes, being simple tubes with two or more lenses. The first practically used
compound microscope was invented by the Janssens in 1590 (Singer, 1914). The compound
microscope provided a much higher degree of magnification than the earliest scopes, however
at a cost in clarity due to chromatic aberration and image distortion at higher magnification.
This area of microscope development is most notably remembered for Hook’s detailed analysis
published in his Micrographia in 1665 (Mazzarello, 1999), the work that coined the term “cells.”
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The time period starting in the early 1800s to
present has been predominantly focused on
eliminating distortions and aberrations so that
compound microscopes could be pushed to
their absolute resolution limit (Singer, 1914).
We will return to a discussion of the resolution
limit of a compound microscope later. The first
optical aberration we will discuss is chromatic
aberration. This type of defect is caused
because white light is actually composed of
many different colors of light. As an example, consider a prism. On one side white light goes in
and on the other a rainbow comes out (Figure 1). This is because the degree of refraction (the
bending of the light) is dependent on the wavelengths of the light. The shorter wavelengths are
refracted less than the longer wavelengths. In this case, the prism is a basic lens. Therefore, in
a compound microscope that uses white light, the different wavelengths that compose this light
would focus at different points because they are each refracted a different amount. This
produces a color blur around objects (chromatic aberration). Over many years this problem
was fixed with the development of compound lenses which are composed of multiple lenses.
In this case, each of the sub-lenses has a different refractive index. This brings the focal point of
the different wavelengths of light
back together (Ernst, 1900).
These are called achromatic or
apochromatic lenses.
The other type of distortion is
curvilinear distortion which is the
tendency to bend straight lines
into curves. An example that you
are likely familiar with is the
fisheye effects seen in wide angle
photography. The reason for the
distortion is that light bends as it
strikes a lens at a non-perpendicular angle. In order to get the high degree of magnification
needed in early compound microscopes, the single lenses that were used had very curved
surfaces. This meant that the light at the edge of the lens was bent much more than the light
from the center of the lens. To correct this, microscope builders again used compound lenses.
In this case, the sub-lenses have different shapes (Ernst, 1900). The different shapes will affect
the bending of the light rays so that the light rays are brought back perpendicular to each
other. Since the shape of a lens changes its effect on light, multiple lenses can be used to shape
light in many different ways. Figure 2 shows the effect of different lenses on light rays.
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Over the last several decades, the development of modern microscopes has begun to be
focused on the resolution limit. The resolution of a microscope is defined as the ability of the
observer (person or camera) to distinguish between two objects that are close together. In
1873, Ernst Abbe showed that the theoretical resolution limit of a diffraction microscope was
half the wavelength of the light being used (Lipson, 2011). Therefore the resolution limit of an
optical microscope is about 190 – 350 nm (the human eye responds to light with wavelengths
of 390 – 700 nm). To get better resolution than is possible with a compound microscope,
scientist started using electron beams with scanning and tunneling electron microscopes that
have wavelengths 100,000 times smaller than visible light (Scherzer, 1949). Recently, work
using lasers and quantum mechanics has begun to develop microscopes that “break” the
resolution limit of optical microscopes; however, we will not discuss these types of microscopes
further in this protocol.
Since the resolving power of a microscope also indicates how much magnification you
theoretically have, the type of microscope you use depends on the type of observations you are
conducting. We will now briefly cover the other types of microscopes you should be familiar
with. In addition to the compound microscope, you should be familiar with the dissecting and
electron microscopes.
Of the three types of microscopes, the dissecting microscope has the lowest magnification. The
magnification range of a dissecting microscope is 10x to 40x. It provides a view of a fairly large
sample for the purposes of detailed examination and/or dissection. Typical subjects might be
small animals, whole flowers, or organ parts. Dissecting microscopes are used to magnify
specimens of sizes 10 μm to 0.1 m. If a dissecting microscope has two ocular lenses on separate
body tubes, it is a stereoscope dissecting microscope. The dissecting microscope uses visible
light which is brought in from the side of the sample.
The compound light microscope has a magnification range that place it between the dissecting
microscope and the electron microscopes. The magnification range is 40x to 2000x. Typical
subjects might be cells, large cellular organelles, and bacteria. Compound microscopes are
used to magnify specimens of sizes 200 nm to 5 mm. The compound microscope uses visible
light which is brought in from below the sample. Since the light must shine through the
specimens, it must be small or thinly sliced to obtain a good image. Since you will be using this
type microscope exclusively in this lab, we will also discuss the components and parts of this
microscope.
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In a modern compound microscope, there
are three main optical components
(Figure 3). They are the condenser
(Figure 3a), objective (Figure 3b), and the
eye piece (Figure 3c). The condenser
focuses the light from the light source
onto the underside of the sample. The
objective contains a complex series of
lenses that correct chromatic aberration
and image distortion. The objective also
gives part of the microscope’s total
magnification. The objectives are
mounted into a wheel that allows the user
to select which objective they wish to use.
The length of the objective is often related
to its magnification with longer objectives
having higher magnifications. One of the
reasons that the objectives are different
lengths is so that the microscope will be
par-focal at all magnifications which
means that the object that is in focus at
10X will also be in focus at 20X, 40X, 60X,
etc. The eye piece gives the final part of
the magnification such that the total magnification of a microscope is determined by
multiplying the objective by the eye piece. As an example, if you’re using a 10X eyepiece and
20X objective, your total magnification will be 10 x 20 = 200X.
The electron microscopes have the highest effective magnification of the microscopes we are
discussing. Electron microscopes come in two types. The scanning electron microscope (SEM)
and the transmission electron microscope (TEM) each type employs electron bombardment to
image very small specimens. In the SEM, the electrons pass through a three dimensional
specimen and are “read” using a detection device. A computer reconstructs the specimen
image from the information gathered by the scanning process. The magnification range of an
SEM can reach 200,000X and provide great detail. The TEM allows internal investigations of the
internal structure of prepared specimens. The TEM can reach up to 50,000,000X which is a
higher magnification range than the SEM. Electron microscopes are used to image samples that
range from 1 nm to 100 μm in size.
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References:
Ernst, H.C. (1900). The Development of the Microscope, J. Boston Soc. Med. Sci. 4, 148–152.1.
Julius Sachs, I.B.B. (1890). History of Botany (1530-1860) (Clarendon press).
Lipson, A. (2011). Optical physics (Cambridge ; New York: Cambridge University Press).
Mazzarello, P. (1999). A unifying concept: the history of cell theory. Nat. Cell Biol. 1, E13–E15.
Organization, N.P. Microscopes: Time Line.
Scherzer, O. (1949). The Theoretical Resolution Limit of the Electron Microscope. J. Appl. Phys. 20,
20–29.
Singer, C. (1914). Notes on the Early History of Microscopy. Proc. R. Soc. Med. 7, 247–279.
PRE-LAB EXERCISE 1: The Microscope
There are many types of microscopes available for biologist to use. The functionality of
these microscopes is dependent on many factors. Which type of microscope you choose to
use is dependent on the particular task you are trying to accomplish.
Pre-Lab 1 Questions:
1. One of the most common types of microscope in use today is the compound light
microscope. What property of this microscope’s construction gives it the name
“compound microscope”?
2. Complete the following table of magnifications.
Microscope Objective
Total Magnification
10X Eye Piece
20X Eye Piece
4X
10X
20X
40X
60X
Use the microscope types in the following list to answer the following questions. The names may
be used more than once.
Dissection Microscope
Compound Microscope
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Scanning Electron microscope
Transmission Electron microscope
3.
4.
5.
6.
The _____________________ microscope has the highest magnification.
The _____________________ microscope is used to examine a whole organ.
The _____________________ microscope has two or more sets of lenses.
The _____________________ microscope uses light from the side to illuminate its
sample.
7. The _____________________ microscope can generate magnifications of 200,000X.
8. The _____________________ microscope used to look at whole cells or larger cellular
organelles.
9. Label the parts on the following diagram of a compound microscope.
10. You are trying to build a light microscope with the best resolution possible. To do this
your light source is going to be a single wavelength of visible light. You have single
wavelength light-emitting diodes in Infrared, Red, Orange, Green, Blue, and Violet.
Which one will you use as your light source and why?
PRE-LAB EXERCISE 2: Field of View and Depth of Field of a
Compound Microscope
It is important to remember that the sample you are looking at in your microscope is actual a
three dimensions object it has height, width, and depth. In microscopy we refer to these
dimensions as the X, Y, and Z axis. We need to remember this because the different objectives
on a microscope will display different amounts of each of these axis. Therefore, when you are
examining a sample under the microscope you need to know both how much of the sample is
visible and what part of it you are viewing. We determine how much of the sample we are
viewing based on the amount visible to the ocular or the camera, this area is called the field of
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view. The field of view is a plane parallel (the x and y axis) to the slide and can be easily
quantified using a ruler. The ruler we use with a microscope is called a stage micrometer.
While it might seem intuitive the part of the sample you see is the part that is in focus, what we
call the focal point. We always need to remember that there may be parts of the sample either
above or below the focal point that we cannot see. The amount of the sample that is in focal
point is called the depth of field (the Z axis). The depth of field is perpendicular to the field of
view. However, depth of field is much harder to measure then field of view and we will only be
dealing with depth of field qualitatively in this lab. Both field of view and depth of field are
related to and affected by the magnification of the objectives. In this section you will explore
the relationship between the objective’s magnification and the field of view and depth of field.
Pre-lab 2 Questions
1. How do you think the depth of field and field of view will change as magnification
increases.
Scientists utilize a specific methodology when conducting experiments. This process is
called the scientific method. Very simply, in the scientific method you ask a question,
make a prediction, test that prediction, and then revise your prediction if necessary.
Your answer to question one in this exercise is a prediction, and the remaining parts of
this exercise allow you to test and revise your prediction. However, scientists craft their
predictions in a specific form called a hypothesis. In order for a hypothesis to be a
scientific hypothesis, it must be both logically valid and testable. One way to write a
hypothesis is to use an If … Then … statement, an example of which would be If the field
of view decreases in diameter Then the depth of field will increase in size. Using this
information, complete the next pre-lab question.
2. Rewrite you your answer to the previous question into an If … Then … hypothesis.
To make measurements on the microscope, you first need to determine the actual size
of the field of view. To do this, you will use a Stage Micrometer which is a microscope
slide that has a small ruler drawn on it. You will use the stage micrometer to measure
the field of view (the visible area) for each objective on the microscope. The
micrometer you will be using is 1mm in total length with 100 divisions.
3. What is the length of one division on the stage micrometer? (Remember to list your
units.)
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PRE-LAB EXERCISE 3: Observation of Cells
In the next exercise, we will look at actual biological samples. The slides we will use are: Elodea Leaf,
Frog Skin, and Mixed Protozoa. We will use these samples to make observations using the microscope
and examine the differences between different types of cells.
Pre-lab 3 Questions:
1. Do you expect to see any differences between the cells in the Elodea Leaf and the Frog
Skin? What differences do you expect to see?
2. Rewrite your answer to question 1 in the format of an If … Than … hypothesis.
3. Do you think the Protozoa will be more like plants or animals? Why?
4. Rewrite your answer to question 3 in the format of an If … Than … hypothesis
EQUIPMENT:




Paper
Pencil/pen
Slides
o Letter "e", Whole Mount
o Colored Threads, Whole Mount
o Stage Micrometer
o Elodea Leaf, Whole Mount
o Frog skin, Whole Mount
o Mixed Protozoa, Whole Mount
Computer with Internet access for the remote laboratory and for data analysis
PREPARING FOR THIS NANSLO LAB ACTIVITY:
Read and understand the information below before you proceed with the lab!
Scheduling an Appointment Using the NANSLO Scheduling System
Your instructor has reserved a block of time through the NANSLO Scheduling System for you to
complete this activity. For more information on how to set up a time to access this NANSLO lab
activity, see www.wiche.edu/nanslo/scheduling-software.
Students Accessing a NANSLO Lab Activity for the First Time
For those accessing a NANSLO laboratory for the first time, you may need to install software on
your computer to access the NANSLO lab activity. Use this link for detailed instructions on
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steps to complete prior to accessing your assigned NANSLO lab activity –
www.wiche.edu/nanslo/lab-tutorials.
Video Tutorial for RWSL: A short video demonstrating how to use the Remote Web-based
Science Lab (RWSL) control panel for the air track can be viewed at
http://www.wiche.edu/nanslo/lab-tutorials#microscope.
NOTE: Disregard the conference number in this video tutorial.
AS SOON AS YOU CONNECT TO THE RWSL CONTROL PANEL: Click on the yellow button at the
bottom of the screen (you may need to scroll down to see it). Follow the directions on the pop
up window to join the voice conference and talk to your group and the Lab Technician.
EXPERIMENTAL PROCEDURE:
Once you have logged on the microscope you will perform the following Laboratory procedures:
EXERCISE 1: Operating a Compound Microscope
In this exercise, you will learn how to operate a compound light microscope. When the exercise is over,
you will understand how to position a sample, focus the microscope and change the magnification.
Data Collection:
1. Select the letter "e" whole mount slide (Slide Cassette 1: #2) from the microscope
interface.
2. Place the letter e in the center of the field of view and focus on it with the 10X objective.
First, we are going to examine the effects of magnification.
3. In the space below is a diagram of the slide as it is currently loaded on the microscope
(Figure 4 a). In box (Figure 4 b) draw the letter e as you see it in the microscope.
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4. What are the differences between the observed letter e and the letter e mounted on
the microscope? (hint there are two differences)
5. Change to the 20X objective and capture an image of the letter e (If you can’t see any
part of the e go ahead and move the slide). Paste that image below.
6. Change to the 60X objective and capture an image of the letter e (If you can’t see any
part of the e go ahead and move the slide). Paste that image below.
Second, we are going to examine microscope movement.
7. Change back to 10X objective.
8. Now using the microscope controls, click on the top button which moves the stage in
(towards the body of the microscope if you are observing through the PTZ camera) so
that the e moves slightly. How does the e move with respect to the direction the stage
moves?
9. This time, press the left stage control button. This will move the stage to the left
(towards the slide loader if you are observing through the PTZ camera) so that the e
moves slightly. How does the e move with respect to the direction the stage moves?
Analysis:
10. Describe the difference in your observations of the black lines that make up the letter e
using the 20X and 60X objectives.
11. In the three diagrams below (Figure 5), assume that each dashed line represents the
distance the stage will move a single click of the microscope control buttons. Using the
sequence of buttons, draw where the e will be after the button clicks.
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EXERCISE 2: Field of View and Depth of Field of a Compound Microscope
Data Collection:
First, we are going to examine the depth of field.
1. Select the Colored Threads, Wholemount Slide (Slide Cassette 1: #1) from the slide
loader tab.
2. Examine the slide with the 10X objective and describe what you see.
3. How many of the threads can you get in focus using the 10X objective? Which of the
threads is on top, in the middle, and on the bottom? Capture an image, using your word
processor, label the top, middle, and bottom thread. Paste it below.
Change to the 20X objective, how many of the threads can you get in focus
simultaneously?
4. Capture an image and paste it below.
Second we will examine the field of view.
5. Select the Stage Micrometer slide from the slide loader tab, center, and focus the
micrometer in the field of view.
6. Create a table to record the diameter of the field of view for each of the objectives.
7. Select each objective in turn and measure the diameter across the middle of the visible
area. Record your measurements the table you created in step 9, each group member
should collect a set of data. Paste your table with all the group's data below.
Analysis:
8. What happens to the depth of field as the magnification increases?
9. Take the table you created in step 10 and add two columns to it. In the first column,
average the diameter measurements for all your group's data. In the second column,
convert the mm lengths into µm lengths.
10. What happens to the field of view as the magnification increases?
11. Refer back to the If … Then … hypothesis you created in Pre-Lab Exercise 3, question 2.
Was your prediction correct? Explain why or why not
12. Rewrite your hypothesis in light of the information you learned performing this
experiment.
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EXERCISE 3: Observation of Cells
Data Collection:
1. Select the Elodea Leaf, whole mount (Slide Cassette 1: #4) from the slide loader tab.
2. Center and focus the sample in the field of view. Change to the 40X or 60X objective.
Capture an image of the leaf cells. Paste the image below.
In the previous exercise, we determined the diameter of your field of view. We will use
this information to determine the size of the Elodea cells.
3. Create a table to record your data.
4. Change your objective to 40x and move to an area so that the leaf cells completely fill
the field of view.
5. Position the slide so that the left edge of a single cell is on the left edge of your field of
view. Count how many cells in a single row that reaches all the way across to the right
edge of the field of view.
6. Repeat step 9 three more times with different rows of cells. Paste your table below.
7. Select the Frog Skin, Whole Mount (Slide Cassette 2: #33) from the microscope
interface.
8. Center and focus the sample in the field of view. Change to the 40X or 60X objectives.
Capture an image of the Frog Skin cells. Paste the image below.
9. Select the Mixed Protozoa, Whole Mount slide (Slide Cassette 1: #6) from the
microscope interface.
10. Find some protozoa on the slide. Center and focus the sample in the field of view.
Change to the 40X or 60X objective. Capture an image of the protozoa. Paste the image
below.
Analysis:
11. Using your word processor and the image you captured in step 6, label all the structures
you can identify in a leaf cell (examples: nucleus, cell membrane, cytoplasm, cell wall
etc.). Paste the image below.
12. Next we are going to determine the size of the leaf cells. Start by averaging the number
of cells it takes to fill your field of view from top to bottom. Insert that number below.
13. Next divide the diameter of your field of view by the average number of cells. This will
give you the size of your cell. Insert that number below (make sure to include your
units).
14. Using your word processor and the image you captured in step 12, label all the
structures you can identify in a Frog Skin cell (examples: nucleus, cell membrane,
cytoplasm, cell wall etc.). Paste the image below.
15. Did your observations identify any differences between plant and animal cells? How do
these differences compare to your hypothesis?
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16. Using your word processor and the image you captured in step 14, label all the
structures you can identify in a protozoa cell (examples, nucleus, cell membrane,
cytoplasm, cell wall etc.). Paste the image below.
17. Based on your observation about the protozoa, are protozoa cells more like plants or
animal cells? Explain.
Until fairly recently all organisms were classified into one of the five kingdoms of life
(Monera, Fungi, Protista, Plantae, and Animalia). This classification system was based
on physical appearance and in some cases physiology. More recent studies using DNA
sequence comparison has shown that all living organisms belong to three Domains of
life Bactria, Archaea, and Eukaryota. In this system, it was realized that Plants, animals,
and Protista all belong to the Eukaryota domain.
18. In light of the idea that plants, animals, and Protista are all separate groups of the
Eukaryota domain, does your observations about the Protista make more sense? Why?
SUMMARY QUESTIONS:
1. You are looking at a sample at 10X. When you increase the magnification to 40X, the
sample is no longer in the field of view. Why might this happen, and how would you
correct it?
2. If the compound microscope is par-focal, explain why sometimes when you go from the
10X or 20X object to the 60X object is the sample not in focus.
3. If an electron microscope has the highest resolution and magnification, why do we still
use dissecting and compound microscopes?
4. Why does an electron microscope have a higher magnification and resolution than a
compound light microscope?
5. Given the following slide, draw how the sample would appear while looking through the
microscope (Figure 6).
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6. It is important to understand how light moves through a microscope. Complete the
diagrams in Figure 7 to show the light path. In Figure 7a, draw the mirror that is needed
to direct light to the ocular instead of the camera. In Figure 7b, draw the path that the
light takes to reach the ocular. In Figure 7c, draw the path the light takes to reach the
camera.
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For more information about NANSLO, visit www.wiche.edu/nanslo.
All material produced subject to:
Creative Commons Attribution 3.0 United States License 3
This product was funded by a grant awarded by the U.S.
Department of Labor’s Employment and Training Administration.
The product was created by the grantee and does not necessarily
reflect the official position of the U.S. Department of Labor. The
Department of Labor makes no guarantees, warranties, or
assurances of any kind, express or implied, with respect to such
information, including any information on linked sites and
including, but not limited to, accuracy of the information or its
completeness, timeliness, usefulness, adequacy, continued
availability, or ownership.
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