Biology 140
– Human
Biology
Lab
Notebook –
Intro and
Microscopes
Laura Ambrose
Luther College © 2012
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Contents
Acknowledgements................................................................................................................................... 2
Introduction to the labs ................................................................................................................................ 3
How to use this lab notebook ................................................................................................................... 4
Lab Procedures and Safety........................................................................................................................ 4
Student Accessibility ................................................................................................................................. 4
Microscopy .................................................................................................................................................... 5
Introduction .............................................................................................................................................. 5
Background ............................................................................................................................................... 7
Readings .................................................................................................................................................... 9
Pre-lab Questions...................................................................................................................................... 9
Lab activities and worksheets ................................................................................................................. 10
Lab assessments...................................................................................................................................... 24
Bibliography ............................................................................................................................................ 29
Acknowledgements
Thank you to Carolyn Gaudet and Jody Rintoul for their dedicated teaching of the BIOL 140 labs. Their
efforts have greatly contributed to this lab manual, the lab course, and the learning experiences of the
students. Thank you to Carolyn and Jody for editing and proofreading this second edition of the manual.
Thank you to Terry Ross and Heather Dietz for sharing their expertise in teaching labs. Thank you to
Luther College and the University of Regina for supporting my efforts at delivering quality education
experiences to the students enrolled in the non-majors biology courses.
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Introduction to the labs
Welcome to the exciting world of Biology 140 labs! This is the place where the topics introduced in
lectures are brought to life through observation, experimentation and discussion. Throughout the
semester you will observe the microscopic, solve a mystery, examine your genetics and experiment on
your own body!
The purpose of taking a lab class is to provide you with an opportunity to broaden your knowledge base.
That sounds like a cliché, but it is very true that having exposure to disciplines outside of your area of
study will make you more successful in your chosen field. This Human Biology course is a great course to
take because you are already fairly well-versed in the subject, being a human yourself! What you are
going to learn in this class, and what is highlighted by the labs, are some of the processes that keep our
body functioning and healthy. As you work through the lab notebook, you are going to find some of the
information is very familiar to you and other information will be completely new. Bring what you know
and open your mind to new information and let’s get started!
In this lab you will learn some of the basic background knowledge you need to be able to understand
what happens in your body when you are sick, how your body heals itself and how you grew from a
single cell to the trillions of cells you have in your adult body, how you got those brown eyes or (gulp)
receding hairline from your parents, and how some of the organs in your body work together to keep
you alive and kicking! You will use some of the same tools that microbiologists and geneticists use to
determine what bacteria you might have growing in your body and you will work through a “mystery” to
determine how contaminated food makes it way around a party. You will also investigate your genetics,
by looking at the traits of your parents and using the basic genetic prediction techniques that determine
if offspring will inherit traits from their parents. Near the end of the semester you will learn the process
that scientists all over the world use to produce the body of scientific knowledge that is used by
governments to make policies and people to make decisions in everyday life. For example, what does it
matter if food has high fructose corn syrup? As another example, is organic food better for you or better
for the environment or both or neither?
You know that dip stick in a car? The one that measures how much oil is in the car? It would be really
great if your brain came with a dip stick so I could measure how much biological information you have;
but, well, I don’t have such a device, and nobody has written a how-much-biology-knowledge-is-in-thisbrain app yet, so I have to resort to more manual forms of assessing how much you learn. In the lab you
will be doing some writing, some group activity work, and an exam. In each lab there will be activities
that you will complete that the lab Teaching Assistant will come by and check, just to make sure you are
understanding the concepts and on the right track. In the lab notebook you will see places marked
TA Checkpoint
indicating where you need to show something to the TA. Sometimes the lab TA will lead a group
discussion instead of visiting each student. When that happens, you will be responsible for ensuring you
have the correct answers, as discussed in the lab. For some of the labs you will need to continue working
on your lab activities at home and then hand in your work. An example of this is a lab report at the end
of the semester. Finally, at the end of the semester you will write a comprehensive exam that tests you
on the major processes that you studied during the semester. To help focus your learning and studying,
you will have a study guide for each lab. The study guide will include points or questions to help you
think about what we want you to learn and the study guide will form the basis for the lab exam.
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Let’s get started!
How to use this lab notebook
Although it might seem that the labs are separate from the lectures, they are actually fully integrated
into a whole learning experience. It is important to complete the lab activities and attend lectures in
order to learn all of the things you need to learn to get a credit in Human Biology.
Before each lab session, you should read through the lab notebook, taking note of terms and looking for
activities that you will be completing. Take note of the TA checkpoints so you know where you will need
to get your lab notebook viewed, checked and signed by the lab Teaching Assistant. Take a look at the
suggested readings, including textbook and online readings. Read, think about and answer the Pre-lab
questions.
Preparing before you get to the lab will make things go much more smoothly in lab. Being prepared and
devoting yourself to the tasks during the lab will take you a long way to learning the material you need
to learn for the lab exam, meaning you have less to study later.
Lab Procedures and Safety
It is important to be safe in the lab by following some basic guidelines:
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No eating or drinking except beverages in closed containers.
The lab is a multipurpose space with some equipment, samples, and supplies used for
other classes and they are to be left undisturbed.
Be cautious when moving about the lab as chairs and stools are often pushed out,
creating tripping hazards.
Be careful when using chemicals in the lab. Follow all directions for use and disposal.
Material Safety Data Sheets are available for chemicals used in the labs and are located
in the hallway outside the microbiology lab.
If you have any allergies or sensitivities, please notify the instructor or Lab TA.
Student Accessibility
This lab is accessible. If you have accommodations from the Centre for Student Accessibility, please talk
to the instructor and the lab TA. Remember that accommodations discussions are confidential, so it is
best to make an appointment with the instructor and the lab TA, outside of class/lab hours. The
responsibility for accommodations rests with the course instructor, so please feel free to discuss the
accommodations and any other concerns with the instructor.
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Microscopy
Introduction
In 1665 Robert Hooke used a rudimentary microscope to look at sections of cork, from a tree, and
discovered cells. In 1774 Anthony van Leeuwenhoek observed living single-celled algae and bacteria.
These early explorers of the microscopic world provided the earliest data that informed later
researchers and led to the development of the Cell Theory. These early explorers invented rudimentary
microscopes, lenses stacked on top of each other at varying distances apart, thus starting the process of
invention that created the microscopes used in classrooms, research facilities, hospitals, and forensics
labs.
Microscopes are used to look at things that are too small to be seen with the naked eye. Health care
professionals use microscopes to identify bacteria from an infection, determine if a sample of tissue has
cancer cells, and perform surgery. Researchers use microscopes to find and identify microorganisms in
samples of soil or water, identify insects caught in a river trap, and dissect a study organism. Forensics
scientists use microscopes to look at evidence such as finger prints and bullet casings.
In this lab, we are using microscopes to look at cells and cell structure. The cell is the basic unit of life,
the smallest structure than can survive on its own. Bacteria are single-celled organisms that have
everything that is needed for survival within one cell. The human body is made up of trillions of cells that
have evolved to operate together for the survival of the whole body. Despite the fact that bacteria and
human body cells are extremely different from each other, there are some basic similarities as modern
bacterial cells and human body cells all evolved from the earliest living cells.
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Learning Goals
 To introduce microscopy as a tool in microbiology and medicine
 To give students an appreciation for the wonders of the microscopic world
 To introduce cell structures and functions and how human health relies on the function of
individual cell structures
Learning Objectives
1. After a lesson providing instruction on the proper use of a microscope, the student will be able
to use the microscope to focus on living organisms.
2. After learning the functions of the parts of the microscopes, the student will be able to identify
the parts of the microscope, the function of each part, and how they work together.
3. After a lesson, a demonstration and an activity, students will understand how the Gram stain
procedure is used to begin the process of identifying bacteria.
4. After viewing prepared slides of bacteria that are helpful to humans and bacteria that are
harmful to humans, students will be able to identify shapes of bacteria and begin to understand
how bacteria impact our lives.
Checklist of topics covered and in-lab activities to complete
o Microscope labelling
o How to use a microscope
o Preparing a wet mount
o Looking at the wet mount and pond water
o Look at microbe slides and draw shapes of cells
o Do a Gram stain
o Label the cell diagram
o Find unique structures in the plant cell
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Background
Mary was working in the garden, trying to get rid of all of the weeds that seemed to spring up out of
nowhere. As she was digging out dandelions, the dandelion tool slipped and cut her hand. The cut did
not bleed very much, so Mary did not think about it too much. Later that day she mentioned to her
mother that she had gouged her hand with the dandelion tool and showed her the wound. Mary’s
mother remembered that a cut from something covered in dirt could lead to a very serious infection and
decided to call the Health Line to find out more information. The nurse went through a preliminary
checklist of questions and then confirmed what Mary’s mother had remembered. A very serious
infection called tetanus can occur when a specific bacterium called Clostridium tetani from the soil gets
into the human body and starts to grow and produce toxins. The toxins affect nerves and muscles and
can even be fatal. Mary and her mother realized very quickly that they probably did not have to worry
about any of that, though, because both Mary and her mother had recently had a tetanus immunization
booster shot. Other bacteria could still cause problems, but Mary just needed to watch out for signs of
infection at the site of the wound.
Long before the work of Louis Pasteur (1822-1895) definitively linked microbes and disease, early
microbiologists started studying the basic structure of cells of different kinds of organisms, including
plants, animals, fungi and single-celled organisms such as algae, protists, and bacteria. It is important to
understand the structure of cells in order to understand how they function. After that, the next
challenge is to figure out how the cells interact with each other, including how bacteria might interact
with the human body.
Examples of microscopes and how they are used in research, health testing and forensics
The microscopes we are most familiar with are light microscopes, which are a combination of lenses and
a light source that function together to magnify a specimen. A dissecting microscope is used to look at
or dissect tissue samples or small organisms, such as earthworms. A compound microscope has much
higher magnification power and is used to look at tissue samples and cells. An electron microscope uses
beams of electrons instead of light to view a computer-generated image of the small samples, such as
viruses or molecules.
Introduction to microbes and how humans interact with microbes
As early explorers began to study the microscopic world around them, they began to see that cells were
different from each other and a classification system was created. As microscopes became more
complex and allowed researchers to see more of the cell, including the internal structures, the
classification of cells became more precise. Researchers also use genetic information to classify
organisms.
A prokaryotic cell is a cell that has relatively little internal cellular organization and is defined by not
having a membrane-bound nucleus or organelles. Bacteria, such as Clostridium tetani, are prokaryotic
cells. A eukaryotic cell is a cell that is relatively more complex and is defined as having a membranebound nucleus and organelles. Having this higher degree of internal organization allows a cell to carry
out more complex cellular activities than prokaryotes. Human body cells, along with plants, and fungi, all
have eukaryotic cells. A virus is a slightly different, relatively simple, structure, consisting of some
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genetic information encased within a protein coat and, sometimes, a lipid envelope. There is some
debate about whether or not a virus is a living organism because it can’t carry out any cell functions
outside of a host cell. The Ebolavirus is an example of a virus that can cause illness in humans. This virus
is extremely rare, but was made well-known in the 1995 movie Outbreak. A more common virus that
infects humans is the Adenovirus which causes respiratory illness as it infects human respiratory tissues.
The Gram Stain is a technique that is used to identify bacteria based on cell wall structure. Bacteria can
be classified into one of two groups, based on molecules present in the cell wall. The technique uses a
series of steps to dye and rinse a sample of bacteria. After the Gram staining procedure is completed, a
light microscope is used to determine if the cells are Gram positive or Gram negative. The Gram stain is
often the first step in identifying an unknown sample of bacteria. One well-known Gram negative
bacterium that causes gastrointestinal illness in humans is Escherichia coli. A well-known Gram positive
bacterium is Clostridium tetani, the one that causes tetanus.
Cell structure and function
The cell theory was developed based on the work of many early microscopic explorers. Roughly 200
years after the first cell was seen in a rudimentary microscope, the main ideas of the cell theory were
set down: 1) cells are the basic unit of life, 2) living things are made up of at least one cell, 3) cells arise
from existing cells.
Cells contain smaller structures that operate to keep the cell alive and allow it to carry out its functions.
For example, inside of a pancreatic cell called an islet cell, there are structures that know how to put
together the insulin that is needed in order to get energy from the food we eat. These internal
structures are called organelles.
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Readings
In order to be able to complete your lab on time and get the most out of it, complete these readings and
view the videos or animations before your lab period.
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Chapter 3 – microscopes and cell structure
Microbe World
(http://www.microbeworld.org/index.php?option=com_content&view=article&id=87&Itemid=5
9)
How Big? (http://www.cellsalive.com/howbig.htm) - online activity
Cell Biology (http://www.biology.arizona.edu/cell_bio/tutorials/cells/cells.html ) - introduction
to cells, scientific method, and cell biology history
Gram Stain procedure (video) –
http://www.youtube.com/watch?v=8zd3HPRxx1U&feature=related
Pre-lab Questions
Think about the following questions and points as you prepare for the lab.
1. Look around your house to find places where you benefit from the knowledge of
microbiologists. Look at food labels, medicines, and think about times you have visited the
doctor.
2. Can you think of ways that you interact with microorganisms?
3. What do you know about microscopes? Have you used one before?
4. There are many kinds of microscopes. Why are we using a light microscope instead of another
kind of microscope?
5. What kinds of things can you look at under a microscope?
6. How might a microscope help a surgeon?
7. Why is it important to understand the structure of cells?
8. Single-celled organisms have everything they need to survive whereas multicellular organisms
have highly evolved cells that interact with each other.
9. An athlete trains in the Andes and another athlete trains in Vancouver. How might the
organelles in their cells be different? If you want a hint: mitochondria
10. Do you know of any diseases that occur because cells don’t function properly?
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Lab activities and worksheets
Read through this section before you get to lab so you are aware of what you will be doing during the
lab period.
Microscope labeling
It is important to know the structure of something in order to know how it works and how to use it. Use
the following list of parts of a compound microscope to label the diagram. Be sure to understand the
functions of each part.
Ocular: this is the lens at the top of the microscope, the one you look through. It usually has a
magnification of 10 times (10x). It may contain a pointer that is used to point to something on the slide.
Objectives: a compound microscope has 3 or 4 lenses that sit directly above the specimen and can be
rotated into place. The shortest has the least magnification and the longest has the most magnification.
- Scanner – 3 or 4 times
- Low power – 10 times
- High power – 40 times
- Oil immersion – 100 times (not all microscopes have oil immersion)
Arm: connects the objective lens to the base
Base: the bottom
Illuminator: the source of light, usually a lamp sitting on the base, but it could be an external lamp
Condenser: located just below the stage, the condenser focuses the light from the illuminator onto the
specimen. The adjustment knob raises and lowers the condenser.
Diaphragm: regulates the amount of light going through the condenser to the specimen. The
adjustment lever, handle, or knob opens and closes the diaphragm. Using the condenser and the
diaphragm together provides the light necessary to see the specimen.
Stage: the platform where the specimen sits. The specimen is on a slide which is placed on the stage.
Nosepiece: the revolving nosepiece sits below the ocular lens and it houses the objective lenses. The
nosepiece will rotate to move the various objective lenses into position.
Coarse adjustment: moves the body tube and the objective lenses over greater distances and is used for
getting a specimen into course focus at very low magnification, using the scanner objective.
Fine adjustment: moves the body tube and the objective lenses small distances and is used for fine
focus at higher magnification, using the low power, high power, or oil immersion objectives.
Stage clip: holds the microscope slide in place on a compound microscope.
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Compound Microscope Diagram – Label each of the parts
This activity is a TA Checkpoint. Have this diagram checked and initialled by a lab Teaching
Assistant.
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How to use a compound microscope
1. Grasp the microscope firmly by the neck and the base, using 2 hands. Place it gently on the
counter.
2. Use the coarse adjustment knob to move the lenses as far away from the base as possible.
3. Turn the nosepiece so the scanner lens is in position (you will hear a faint click when the lens is
in place).
4. Turn the diaphragm so the most light possible is coming through the condenser.
5. Place a slide on the stage, holding it in place with the clips.
6. Move the lens closer to the stage using the coarse adjustment knob. From the side, you should
see the lens about 3 mm above the slide and when you look through the objective lens you
should see the specimen at a high level of viewing. Always move the lenses slowly when you
have a specimen on the stage. Use the fine adjustment knob until the slide is in crisp focus
7. Adjust the diaphragm if necessary to eliminate glare.
8. Swing the low power lens into place.
9. Adjust the focus with the fine adjustment knob.
10. If necessary, swing the high power lens into place and adjust the focus with the fine adjustment
knob. You will not need the oil immersion lens (100x) in this lab.
11. Never use the coarse adjustment with any lens other than the scanner. Always move the
lenses slowly when focusing on the specimen.
You can calculate the total magnification by multiplying the magnification of all of the lenses used to
look at a specimen. For example, if you are looking at a slide of cells and you are using the ocular lens
and the low power lens, you are magnifying the object by 100 times. The ocular lens is 10 times
magnification and the low power lens is 10 times magnification, so 10 x 10 = 100 times total
magnification. You are looking at the cells 100 times bigger than their actual size! Fill in the following
table, calculating the total magnification for each combination of lenses.
Lens 1
Ocular
Lens 1 magnification
Lens 2
Scanner
Ocular
Low power
Ocular
High power
Lens 2 magnification
Total
As you look at your specimens, you can slowly move the fine adjustment knob up and down to focus
through the depth of the specimen. This allows you to see the 3-dimensional structure of the specimen.
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How to prepare a wet mount
Specimens are usually placed on a microscope slide and covered with a cover slip. It is fairly easy to
make a wet mount of a specimen. Remember to always handle the slide and cover slip by the edges, not
the flat surfaces. Use a piece of lens paper to clean the slide and cover slip, if necessary. The lens paper
can be used by more than one student. Practice making a wet mount using a letter e from the
newspaper.
1. Using the provided newspaper, find and cut out a letter “e” that is not more than 3mm in size
and has printing on one side only, if possible.
2. Place the piece of newspaper on the centre of the slide, printed side up.
3. Place a single drop of water on the piece of newspaper, using an eye dropper. The water should
soak into the newspaper and surround it.
4. Place the cover slip on the slide by placing one edge of the cover slip into the water at about a
45 degree angle and gently lowering the cover slip into place. A few bubbles may get trapped,
but you can gently tap them out. As long as the bubbles are not on top of the “e” they will not
interfere with viewing the specimen.
5. Place the slide on the stage and follow the steps for focusing the microscope.
Note the orientation of the letter “e” on the stage. What orientation does the letter “e” have when
viewing it with the microscope?
This activity is a TA Checkpoint. Have your drawing of the letter “e” checked and initialled by a lab
Teaching Assistant.
Pond Water
The world is alive with microscopic organisms. Collect a drop from the container of pond water, which
may have been collected from Wascana Lake or it may have been constructed from purchased samples
of microorganisms that are commonly found in pond water. Place the drop on the slide, add a cover slip
and observe the living cells. You may have to move around the slide to find organisms. Imagine you are
Anthony van Leeuwenhoek (minus the curly wig and robes) discovering tiny moving cells, which he
called animalcules, or tiny animals.
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Bacteria shapes
Bacteria are everywhere! You find them on your body and inside your body. They are also in the air we
breathe, the water we drink and in the food we eat. We depend on them for survival in our intestines as
they provide essential vitamins. We take advantage of them in food production, such as beer, cheese,
and bread. We fight them when the wrong ones (pathogenic) grow out of control on or in our body. We
are also irritated by them when they manage to get into our food and cause spoilage, such as in soup or
stew. Bacteria are single-celled organisms that do not have a membrane-bound nucleus or organelles,
but they do have a cell wall that develops into characteristic shapes that are used to categorize them.
There are 4 basic shapes with many variations that are used to group the species of bacteria into broad
and then specific categories. These shape categories become part of the classification of the bacteria
into species. For example, Streptococcus pyogenese is a bacterium that causes food poisoning, scarlet
fever, and impetigo.
1. Coccus (cocci, plural): sphere
a. Diplococcus: two spheres attached to each other
b. Streptococcus: a chain of spheres
c. Staphylococcus: grape-like cluster
2. Bacillus (bacilli, plural): rod
a. Streptobacillus: a chain of rods
3. Spiral: helix or corkscrew
a. Vibrio: comma-shaped
b. Spirillum: rigid spiral
c. Spirochete: flexible spiral
For this next activity you are going to use a slide viewer and a strip of images of common microbes. The
images have been magnified to varying degrees to give you the best view of each organism. Take a look
at the microslide and draw a sample of one cell, or a few cells, of each species on the microslide.
Bacteria are fairly simple, so your drawings will be fairly simple. Don’t worry about the colours of the
bacteria because the cells can be stained with almost any colour.
Use the information cards that accompany the microslides to make a few notes as to how the bacteria
you looked are helpful to humans or harmful to humans. You should look at 4 examples from the Helpful
microslide and 4 examples from the Harmful microslide.
Species are named using a formal system called binomial (bi-two; nom-name) nomenclature. The names
are written in Latin and follow international codes of rules. The two parts of the species name are the
two lowest levels on the classification system developed by Linnaeus. The first part is the genus name
and the second part is the species name. A genus is a group of species that are similar to each other. The
genus name is analogous to the family name that indicates people that are in one family. The species
name refers to one species. For example, humans have the Latin name, Homo sapiens. Homo is the
genus name and sapiens is the species name. Note that the Latin names are italicized to offset them
from the English words. It is also acceptable to underline the Latin names.
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Practice writing the following names in the form of a Latin binomial:
Common name
Blue grama grass
Saskatoon berry
Latin name
BOUTELOUA GRACILIS
AMELANCHIER ALVIFOILA
Tiger shark
GALEOCERDO CUVIER
Baker’s yeast
SACCHAROMYCES CEREVISIAE
Crab louse
PEDICULOSIS PUBIS
Binomial form
Bouteloua gracilis
It is expected that you will use the proper binomial names and write them correctly, when appropriate.
In the spaces provided, write the name of the organism you looked at, draw a simple diagram, and make
a few jot notes. Use the information cards to find out the name of the organism.
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Name:
Name:
Name:
Name:
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Name:
Name:
Name:
Name:
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Bacterial Identification using the Gram Stain
(Adapted from Biology 101 lab manual, P. Leavitt and T. Ross)
Identification of bacteria is more challenging than identification of larger organisms because it is difficult
to see the morphology (the form or structure) of the cells. Bacteria are different from each other, just as
corn is different from grass and lions are different from tigers. Bacteria can be differentiated based on
the molecules that make up the cell wall and a process of staining cells has been developed that allows
identification into two broad categories: Gram positive (Gram +) or Gram negative (Gram -).
In this activity you are going to watch a demonstration of doing a Gram stain and then you are going to
do a Gram stain of cells sampled from your oral cavity. The biofilm (a film made from organisms) at the
base of your back teeth is a rich source of bacterial cells. Follow the steps below to do this activity.
Chemicals used in the Gram stain:
Chemical
Crystal Violet
Iodine
Alcohol
Safranin
Purpose
Dye used to stain Gram + cells
Creates a crystal violet-iodine complex that causes
the crystal violet to ‘stick’ to the cell walls of Gram
+ cells
Decolourizer to remove crystal violet from Gram –
cells
A counterstain to stain the Gram – cells red
1. Get the sample. Do this before you begin any other lab activities. Your sample needs time to
dry.
a. For each group of 4, choose two people to collect samples. The best sample will come
from people who have not recently taken antibiotics, smoked, consumes hot beverages
or gargled with antiseptic mouthwash immediately before lab. Use a pencil to label the
end of your slide with your first name and last initial.
b. Using a toothpick, gently scrape some biofilm from the base of a back tooth, close to the
gum line. Take care to not scrape the gums.
c. Smear the sample onto a microscope slide and add a drop or two of water. You need
just enough water to smear the sample into a thin layer.
d. Allow the sample to dry completely.
2. Heat-fix the sample by passing the slide 3 or 4 times over the top of a flame. Allow the slide to
cool for a couple of minutes.
3. Crystal Violet
a. Cover the slide with a couple of drops of crystal violet stain.
b. Let the crystal violet sit on the slide for 1 minute.
c. Gently rinse the slide with water. Rinse the slide into the sink.
4. Iodine
a. Cover the slide with a couple of drops of iodine.
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b. Let the iodine sit on the slide for 1 minute.
5. Alcohol
a. Holding the slide over the sink, drop 95% alcohol onto the slide from a dropper, until
the alcohol runs clear.
b. Gently rinse the slide with water. Rinse the slide into the sink.
6. Safranin
a. Cover the slide with a couple of drops of safranin.
b. Let the safranin sit on the slide for 1 minute.
c. Gently rinse the slide with water. Rinse the slide into the sink.
7. Dry
a. Gently blot the slide dry. Do not rub the slide.
8. Observe
a. Look at the slides using the compound microscope.
Gram stain Classification
Colour
Blue/purple – retained the crystal
Gram +
violet stain
Red/pink – did not retain crystal
Gram violet, stained with safranin
Describe what you see in your slides using words/drawings. You might see the following on your slides:
Object
Cheek cell
Gram +
Gram Other debris (ex. Food)
Description
Large, mostly unstained, large nucleus that
retained some of the stains
Blue/purple
Red/pink
Large pieces that are possibly stained from light
pink to dark purple
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Cell structure
From the most simple to the most complex, cells are highly organized. Bacteria are relatively simple
cells, with no membrane-bound organelles. More complex cells, like those in a human body, have more
internal structures and membrane-bound organelles. In a multicellular organism, like a human body, the
cells have specialized to carry out particular activities that contribute to the survival of the whole
organism. There are some structures and organelles that are common to all cells because all cells need
them to survive.
Parts of the Cell
Form follows function. This small, almost cryptic sentence means that cells, organs, and organisms have
the form, or structure, they need in order to function. If you want to understand the function, you have
to understand the form. Despite the fact that different types of cells do different jobs in the human
body, there are some similarities in cell structure.
Take a look at the cell diagram to see what organelles are present. You should find the following
structures and organelles:
1. Cell or plasma membrane: this is the outermost layer in the animal cell. It is a boundary
between the internal environment and external environment. It regulates what can enter and
leave the cell. It is the site of important chemical reactions.
2. Cytoplasm: this is the internal environment of the cell. It is an aqueous (water-based) solution
where structures, molecules, gases and organelles are found. Molecules, structures and
organelles move through the cytoplasm, as needed.
3. Nucleus: This is the largest organelle inside the animal cell. It contains the genetic information
for the cell and the organism, the DNA. It is also the site of important chemical reactions, such
as replication, transcription, and translation.
4. Rough Endoplasmic Reticulum (Rough ER): this is a membrane with smaller structures
(ribosomes) embedded on it and is the site of protein synthesis. It is located very close to the
nucleus because it works very closely with the nucleus to produce the proteins cells need to
carry out their functions.
5. Smooth Endoplasmic Reticulum (Smooth ER): this is part of the same membrane as the Rough
ER, but it lacks the ribosomes. Important chemical reactions occur on the membrane of the
Smooth ER, including making hormones (testosterone), detoxification (removing drugs from the
blood), and making phospholipids for the plasma membrane.
6. Ribosomes: these are small structures that are either attached to the Rough ER (making it look
bumpy or rough) or floating free in the cytoplasm. Protein synthesis occurs inside of the
ribosome. Cells that produce a lot of proteins, such as beta cells in the pancreas, have a lot of
ribosomes. Ribosomes have two parts, a large subunit and a small subunit, that snap together
when the ribosome is making a protein.
7. Golgi apparatus: a set of flat saccules (small sacs) sitting beside each other. The Golgi apparatus
receives molecules at one end, modifies them, packages them, and sends them out the other
end. Proteins produced on the Rough ER are sent to the Golgi apparatus for finishing and
packaging before being transported out of the body.
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8. Mitochondria: relatively small structures that are highly specialized to carry out the chemical
reactions that convert sugar into ATP. Cells that require more ATP, such as muscle cells, have
more mitochondria.
9. Cytoskeleton: a set of protein fibres of varying sizes that criss-cross through the cytoplasm.
Larger fibres, the microtubules, help maintain the shape of the cell and act as tracks for
organelles and other structures to move along. Smaller fibres, the actin filaments, occur in
bundles and are part of structures that create movement. Sperm cells have long tails made of
actin filaments. Respiratory cells have small projections of short actin filaments that move
debris out of the airway.
10. Lysosomes: small, thick-walled vesicles that contain powerful digestive enzymes. These enzymes
are used to destroy damaged or unnecessary cell parts or invading bacteria or viruses.
11. Phospholipids: a macromolecule made of a hydrophilic phosphate head and hydrophobic lipid
tail. The majority of the plasma membrane is made up of a phospholipid bilayer.
12. Protein channel: a large, tunnel-shaped protein that allows molecules to pass from one side of
the plasma membrane to the other.
13. Smaller proteins: proteins that are found throughout the plasma membrane close to the inner
and outer surfaces. These proteins serve as anchors for carbohydrates, lipids, other proteins,
and cytoskeleton fibres. One other important function of these proteins is they connect with
molecules on the outside of the cell and then trigger a series of chemical reactions through to
the inside of the cell. This is how cells receive environmental signals.
14. Carbohydrate chains: attaches to proteins on the outside of the plasma membrane. These
carbohydrates act as receptors for molecules that pass by the c ell and identify the cell type.
15. Cholesterol: small, dense structures dispersed throughout the plasma membrane. These
molecules maintain the integrity of the membrane as the temperature in the environment of
the cell changes. As the temperature increases, the cholesterol prevents the membrane
molecules from spreading apart too much. As the temperature decreases, the cholesterol
prevents the membrane molecules from compacting together into a solid mass.
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Label the following diagram of an animal cell. Include the 15 structures and organelles listed above. You
will need to know the functions of the 10 structures and organelles, as described in this lab manual. Cue
cards are extremely useful for learning the functions. Draw a diagram or write the name of the structure
or organelle on one side of the card, and put the function on the other side of the card. Study the cards
from both sides. Note that the numbers on the diagram DO NOT correspond to the list of organelles.
They correspond to the cell model and the model key.
This activity is a TA Checkpoint. Have your diagram checked and initialled by a lab Teaching
Assistant.
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Animal, plant or mineral?
We have talked about bacteria cells and animal cells, but not plant cells. Take a look at the plant cell
model and look for three things that are unique to plant cells.
Organelle or structure
Function
Lab assessments
In lab
o Microscope labelled with definitions of parts
o Wet mount of letter “e”
o Cell diagrams labelled with functions of the organelles
Homework
- Study concepts using study guide
- Choose ONE of the following assignments.
1. A three to five page paper on how blood glucose levels are regulated. The paper should include
the following parts:
a. One or more paragraphs about how glucose enters the blood.
b. One or more paragraphs about how cells use glucose and what organelles are involved
in using the glucose.
c. One or more paragraphs about the mechanisms that measure how much glucose is in
the blood and how the body responds when glucose levels rise above what is normal for
maintaining homeostasis.
d. One or more paragraphs about what happens when there is a breakdown in the
regulation mechanism resulting in diabetes.
e. Proofread essay for spelling and grammar. Use the following references to start your
research. Include all of your sources of information, including dictionaries and
Wikipedia. You should have 2 sources of information for each fact you present. At
minimum, you will have 2 sources. For each fact you find in one source, you need to find
it again in another source, to make sure your information is correct. For an assignment
like this, you should have 3 or 4 sources.
i. (http://www.hbci.com/~wenonah/new/cellengy.htm)
ii. Video: http://www.mayoclinic.com/health/blood-sugar/MM00641
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Marking Checklist for Blood Glucose Paper
Description
Paper Content
 Well-written introductory sentence
 Explanation of what glucose is and how it is used in human cells, including the
organelles involved
 Explanation of how glucose is acquired by the body and how it eventually ends up
in the cells
 Explanation of how our body knows how much glucose is in the blood and how
the body responds to either high or low glucose levels
 Explanation of what diabetes is and how it is treated
 Explanation of a novel treatment for diabetes
Presentation and References
 Neat, organized, and easy to read
 No/few grammar and spelling mistakes
 Images
 Evidence of learning beyond the parameters of the assignment (you only get
these pointes if all/most of the other points are achieved)
Total points achieved
Points
Total: 27
/2
/5
/5
/5
/5
/5
Total: 8
/2
/2
/2
/2
/35
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2. Create a Wanted Poster for a microbe. The focus of this assignment is on the microbe that
causes the disease or condition. You are going to create a typical Wanted: Dead or Alive poster
(do a Google images search to get examples).
a. On the front you need:
i. the name of the culprit (Latin and common name(s))
ii. the disease it causes
iii. a picture of the culprit (you can draw or insert an image)
iv. description of the culprit (shape, size, gram stain, etc.)
b. On the back you need:
i. transmission of the disease from host to host, including any vector or reservoir
organisms
ii. incubation period of the disease (how long does it take for the symptoms to
show?)
iii. the treatment for the disease
iv. the preventative measure to avoid the disease
v. Incidence of this disease around the world. Where is it common?
vi. Bibliography of sources, including dictionaries and Wikipedia
vii. Make sure the image is not copyrighted. You can use images from Wikipedia as
long as you cite your source.
c. Details:
i. The poster should be at 8x11 inches.
ii. The majority of the marks will come from the content, but you will also be
marked on your presentation. You should create this poster as if it will be on
display in the hallway.
iii. Proofread your poster for grammar and spelling.
iv. Include all of your sources of information, including dictionaries and Wikipedia.
You should have 2 sources of information for each fact you present. At
minimum, you will have 2 sources. For each fact you find in one source, you
need to find it again in another source, to make sure your information is correct.
For an assignment like this, you should have 3 or 4 sources.
v. Start with the following sources:
1. http://www.nlm.nih.gov/bsd/pmresources.html
2. http://www.ncbi.nlm.nih.gov/pubmed
3. http://www.nlm.nih.gov/medlineplus/
4. http://www.cdc.gov/
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d. Choose from one of the following illnesses or conditions. Remember to focus on the
microbe, not the illness or condition. For example, in your poster you would say
“Wanted: Bacillus anthracis for causing Anthrax, NOT “Wanted Anthrax”. If you are
having trouble finding all of the required information, choose another illness or
condition.
Pathogen
Rhinovirus
Influenza virus
Polio virus
Variola
Rubella
Varicella
Ebola virus
Hepatitis B Virus I
Herpes simplex virus
Varicella zoster
Corona Virus
HIV(human immunodeficiency virus)
Treponema pallidum
Coxsackievirus A16
Bacillus anthracis
Bordetella pertussis
Clostridium botulinum
Clostridium tetani
Mycobacterium leprae
Mycobacterium tuberculosis
Neisseria gonorrhoeae
Neisseria meningitidis
Salmonella typhi
Salmonella typhimurium
Shigella dysenteriae
Streptococcus pneumoniae
Streptococcus (group A)
Vibrio cholerae
Streptococcus pyogenes
Borrelia burgdorferi
Helicobacter pylori
Yersinia pestis
Disease
Common cold
Influenza
Poliomyelitis
Small pox
German Measles
Chicken pox
Ebola
Hepatitis B
Cold Sores
Shingles
SARS
AIDS
Syphilus
Hand, foot, and mouth disease
Anthrax
Whooping cough
Botulism
Tetanus
Leprosy (Hansen's disease)
Tuberculosis
Gonorrhea
Spinal meningitis
Typhoid fever
Food poisoning
Dysentery
Pneumonia
Scarlet fever
Cholera
Impetigo
Lyme disease
Peptic ulcers
Bubonic plague
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Marking Checklist for Wanted Poster
Description
Front
 Latin name(s)
 Common name(s)
 Disease or condition caused by, or linked to, the microbe


Points
Total: 12
/2
/2
/2
/2
/4
Labelled photograph or diagram of the microbe
Physical description of the microbe
Back
 Transmission
o Host
o Vector
o Reservoir organism
o Method of transmission from one organism to another
 Incubation time
 Treatment
o Physical treatments (surgery, etc.)
o Chemical treatments (drugs, etc.)
o Alternative treatments
 Prevention
 Recurrence after treatment
 Incidence around the world
o Number of cases reported at World Health Organization, if applicable
o Location(s) of case(s) around the world
Total: 25
Presentation, formatting, and resources
 Neat, organized and easy to read
 No/few grammar and spelling issues
 Sources
o >2
o 2
o <2
 Image source
 Evidence of learning beyond the parameters of the assignment (you only get
these pointes if all/most of the other points are achieved)
 All sections have information, with “no information found” (or equivalent words)
to indicate sections that do not apply or information was not found
Total: 10
Total points achieved
/2
/2
/2
/3
/2
/2
/2
/2
/2
/2
/2
/2
/2
/2
/2
/1
/2
/1
/47
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Study guide
This study guide provides points and questions to help you focus your learning and to help you study for
the lab exam.
1. Know the parts of the microscope, as discussed in lab. Be able to identify the parts of the
compound microscope and explain the functions of each part.
2. Contrast the three kinds of microscopes: dissecting, compound, and electron.
3. Contrast the structure of prokaryotic cell, eukaryotic cells, and viruses. Name one characteristic
that is common to all three.
4. Understand how to write Latin binomial names of species.
5. Know the 3 shapes of bacteria (Coccus, bacillus, and spiral) and an example of each.
6. Understand the basic process of the Gram stain, what chemicals are used, an example of a Gram
negative species, and an example of a Gram positive species.
7. Understand the Cell Theory.
8. Know an example of a harmful bacterium and an example of a helpful bacterium. Know the
name or description and how it harms or helps humans.
9. Know the parts of the animal cell and explain the functions of each part.
10. Complete the Cells and Microscopes crossword puzzle. (on URCourses, Lab1)
Bibliography
Cell theory. (2011, August 1). In Wikipedia, The Free Encyclopedia. Retrieved 13:41, August 6, 2011, from
http://en.wikipedia.org/w/index.php?title=Cell_theory&oldid=442477023
Tetanus. (2010, July). In Teens Health, Nemours, Kids Health. Retrieved August 6, 2011, from
http://kidshealth.org/teen/infections/bacterial_viral/tetanus.html?tracking=T_RelatedArticle#
Louis Pasteur. (2011, July 20). In Wikipedia, The Free Encyclopedia. Retrieved 14:34, August 6, 2011,
from http://en.wikipedia.org/w/index.php?title=Louis_Pasteur&oldid=440545325
Virus. (2011, August 5). In Wikipedia, The Free Encyclopedia. Retrieved 15:24, August 6, 2011, from
http://en.wikipedia.org/w/index.php?title=Virus&oldid=443187333
Gram staining. (2011, August 3). In Wikipedia, The Free Encyclopedia. Retrieved 15:38, August 6, 2011,
from http://en.wikipedia.org/w/index.php?title=Gram_staining&oldid=442771650
The Gram Stain, An Animated Approach. Retrieved August 6, 2011. http://bioanimations.blogspot.com/2008/04/gram-staining.html
Bacteria shape: http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/shape/shape.html
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