GENERAL BIOLOGY I
IRSC Biological Sciences Department
GENERAL BIOLOGY I
STUDENT SUPPLEMENTAL
LABORATORY HANDOUTS
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
GENERAL LABORATORY RULES
1.
During the first week of class your instructor will provide you with a schedule
of laboratory exercises. Your preparation is critical. You are expected to be familiar with
the content of each exercise before you arrive in the lab. Read the lab exercise PRIOR to
the laboratory meeting time. Study basic biological concepts dealing with the lab activity
from the lab manual and the lecture text. Laboratory content will not be directly addressed in
lectures.
2.
BE ON TIME (including for Lab Practicals). The laboratory instructor will give
verbal instructions at the beginning of each laboratory. Anticipated difficulties will be pointed
out, special group assignments will be made, and changes in procedure will be noted. Take
careful notes on these instructions. There is not time to repeat these instructions for each
person/group.
3.
A clean work area is a safe work area. Cleanse the tabletop with ethanol prior to
the beginning of each exercise and at the close of your lab. Tabletops should remain clean
and uncluttered at all times. Books, bags, purses and extraneous supplies should be stored
under the student workstation and away from the work surface and traffic areas, such as
around the sinks. Prevent marks on tabletops by laying the plastic sheet from your storage
cabinet or placing a paper towel under your microscope and metal-edged notebooks.
4.
No smoking, eating, or drinking is allowed in the confines of the laboratory!
5.
Keep your hands away from your face. Long hair should be tied back, as a safety
precaution.
6.
Remain serious-minded and methodical to help you to complete assignments on
time and to organize your own material for study. Remember to work independently, but
cooperatively with your laboratory partners and with other groups. Lab group assignments
are considered permanent for the semester and your table and microscope assignments will
be made during the first lab.
7.
Before leaving class on the first meeting be sure to familiarize yourself with the
location of the first aid equipment, fire safety equipment, and emergency evacuation
procedures. Remember to use all equipment and supplies according to directions. Wear
protective gear when it is required. (The lab will supply gloves only when dealing with
human body fluids. You will need to supply protective eye wear, lab coats, and gloves if you
choose to use these during dissections.) Always properly clean and store all equipment at
the end of class, and wash your hands thoroughly upon entering and before leaving the
laboratory. IMMEDIATELY report any injury to your instructor.
Contact IRSC Security:
Main Campus 772-462-4755, x 7777
Chastain Campus 772-519-2623, x5666
Mueller Campus 772-519-2622, x2531
Dixon Hendry 772-528-9322
Pruitt/SLW 772-336-6248
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
8.
Never leave your work station unattended when performing experiments.
9.
Each laboratory exercise format is to a great extent self-explanatory. Before you
begin:
a. Read your lab assignment outlined on the lab syllabus BEFORE coming to
lab.
b. Review your conceptual goals. Prepare flow charts for activities, time required,
etc.
c. Listen to your instructions given by your lab instructor. TAKE NOTES!
d. Organize responsibilities among members of your lab group.
e. Assemble materials required for the activity (from student station or lab
counter).
f. Review the entire activity prior to beginning the actual lab work.
g. Note safety tips, boxed hints or landmarks.
h. In dissection activities, cut and remove very little. Expose organs in
relationship to one another. Consult lab manual diagrams frequently.
i. For microscopic study, make drawings carefully and label significant structures.
j. Always treat all equipment carefully to guard against breakage or damage.
Return all prepared materials to their appropriate locations before the next
class.
k. No materials leave the laboratory setting. No animals used for dissection are
allowed out of the lab. The lab is responsible for the proper disposal of these
animals. Other lab supplies are required for use by multiple lab sections and
cannot be removed from the laboratory. Check the Academic Support Center
(ASC) on Main Campus above the Library for study models, skeleton,
microscopes and slides.
l. Complete your laboratory report carefully before moving to the next exercise.
10.
What do I do if I missed my lab? You will need to attend another regularly
scheduled lab during the activity week as presented on your syllabus. Check with the
instructor to make sure that there will be space available for you. There is an attendance
form that you must sign and give to the “make-up” lab instructor so that your regular lab
instructor will be notified that you attended a lab for that activity.
11.
What do I do if I missed my lab practical? There will be NO makeup practicals
given. Students are to take the scheduled practical during their scheduled lab. Students
missing the final practical and who are passing the course will be given an “Incomplete”.
Otherwise, the final practical will be counted as a ZERO twice. Check your lab syllabus for
further instructions about a missed practical.
12.
What do I do if I need more time to study the lab materials?
A. Use the ASC on Fort Pierce Campus (above the Library), at the Chastain campus
and Okeechobee Campus. There you will find some possible models, charts,
microscope and slides that may help you study for lab practicals
(not all materials available in every ASC lab). Check the days/times for
biology staff tutors at the ASC, if applicable.
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
B. Open lab time. Labs on Main Campus ONLY are open for extra study between
8:00a.m. to 5:00 p.m. on Monday through Thursday (excluding
Holidays) when there is no scheduled lab in the room. Biology faculty or
the Biology Lab Manager will let you into the lab. Students will sign in and
out using the log sheet located on the front desk. Students must leave the
lab at least 30 minutes before the next lab session is to begin. Students
may not provide access to another student. **The lab room is not available
once the lab practical is set up in that room. ******Do not wait till the last
minute. ***** ++No new dissection can take place in open lab unless the
entire dissection group is present.
C. Attend other scheduled labs. You may request permission to attend another
lab section of your lab course, provided there is space available. Be
courteous. Arrive before class to make your request. Do not interrupt the lab
instructor once his/her presentation has started. Be aware that the instructor’s
priority is to the students registered in that lab.
13.
The IRSC Biology Departmental web site is helpful to find schedule of labs for each
biology course, your lab syllabus, photos of cell division slides, etc. Enter the following web
address: http://biology-irsc.weebly.com/ Select “Lab Resources” to access your lab course.
BIOHAZARDOUS WASTE DISPOSAL:
A. Sharps container (small red box) is for human blood or pathogen-contaminated
toothpicks, capillary tubes, lancets and/or slides. Non-contaminated gloves
or paper towels go in regular trash bins.
***Please note the special broken glass bin location in the lab. This is for
any broken glass that is not contaminated with human blood or pathogens.
Please alert your lab instructor of breakage so that necessary replacements
to lab supplies can be arranged.
B. Large pieces of animal tissues and the remains of animals following dissection
are placed in the biohazard bin (or biohazard container indicated by your
instructor) for cremation. Because we respect life, these materials are not
haphazardly discarded in general trash. ***Gloves or paper towels which
have touched dissections are not considered biohazardous and are discarded
in the general trash bin. *Gloves and paper towels contaminated with
human blood are considered biohazardous and are to be placed in the large,
red plastic-lined biohazard bin.
CHEMICAL SAFETY:
Each laboratory table has bottles of water and Ethyl alcohol (Ethanol). The ethanol is a
Class II flammable liquid and must be kept away from heat at all times.
REMEMBER: Use of equipment in the lab is a privilege.
You are responsible for care and correct usage of these facilities and equipment.
Labs are monitored and any misuse of the facilities and its equipment will be noted.
Any irresponsible attitudes or practices MUST be corrected or the laboratory use privileges
will be denied to you in subsequent labs. This is an appropriate setting to nurture your
professional attitudes and behaviors which will put you in good standing in your future
career pursuit.
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
General Biology I (BSC2010) Web Resources
Chemistry/ Biochemistry Tutorials
http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/main.html
http://www.portlandpress.com/pp/books/online/glick/default.htm
Darwin
http://www.literature.org/authors/darwin-charles/the-voyage-of-the-beagle/
Photosynthesis
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html
http://photoscience.la.asu.edu/photosyn/education/learn.html
http://www.quia.com/jg/29139.html
Cells
http://www.biology.arizona.edu/cell_bio/cell_bio.html
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellCycle.html
Membranes
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellMembranes.html
Mendelian Genetics
http://www.sonic.net/~nbs/projects/anthro201/
http://www.biology.arizona.edu/
Chromosomes/Genetics
http://gslc.genetics.utah.edu/
http://www.csuchico.edu/~jbell/Biol207/animations/recombination.html
http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/chooser.shtml
DNA – Structure/Function
http://www.umass.edu/microbio/chime/dna/index1.htm (structure)
http://biology.clc.uc.edu/courses/bio104/dna.htm (structure/function)
http://www.csuchico.edu/~jbell/Biol207/animations/transcription.html (transcription)
http://www.csuchico.edu/~jbell/Biol207/animations/translation.html (translation)
Viruses
http://www.uct.ac.za/depts/mmi/stannard/linda.html
http://biology.about.com/library/blvirusanim.htm
http://www.cellsalive.com/phage.htm (virus and bacteria images)
Phylogeny/Taxonomy
http://www.ucmp.berkeley.edu/exhibit/phylogeny.html
http://tolweb.org/tree/phylogeny.html
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
THE MICROSCOPE:
Parts of the binocular compound microscope (identify parts, know their functions,
know how to clean and care for each part):
Ocular, diopter adjustment, ocular micrometer, pointer, body tube or head,
revolving nose piece, objectives (scanning, low-power, high-power, oil
immersion), arm, coarse adjustment knob, fine adjustment knob, base, light
source, iris diaphragm, iris diaphragm lever, condenser, condenser height control
knob, (pull-out phase adapter), stage, graduated mechanical stage controls,
power switch, electrical cord and plug.
Computation of total magnification of specimen being viewed:
OBJECTIVE
POWER
POWER
TOTAL
OF OBJECTIVE X
OF OCULAR = MAGNIFICATION
Scanning (red band)
4X
x
10X
=
40X
Low-power (yellow band)
10X
x
10X
=
100X
High-power (blue band)
40X
x
10X
=
400X
Oil immersion (white band)
100X
x
10X
=
1000X
From table above, note that total magnification = power of objective times power of ocular.
Care and handling of microscope:
1. Locate your microscope by number in the cabinet. Carry the microscope with
two hands, one under base and other around the arm. Keep the
microscope level, near your body.
2. Place scope gently on the lab table (protect table top with plastic sheet or
paper towel). Do not slide it around on the table; lift it up and set it down.
3. Do not disassemble your microscope or reorient the oculars. The eye pieces
(oculars) face toward you at the same time that the cord holder also faces
you. Report any problems with your microscope to your instructor
IMMEDIATELY.
4. Keep the scope and lens systems clean. Clean lenses only with the lens
paper from your student drawer. Kimwipes may be used to clean base and
stage.
Setting up your microscope at your student station:
1. Remove the plastic dust cover, fold it and place cover in your lab drawer.
2. Unwrap just enough cord to reach the electrical outlet. Do not let cord dangle
off tabletop where it could pull the microscope onto the floor.
Initial focusing of the microscope (for first slide to be studied during a lab period):
1. Clean slide to be viewed by wiping gently with a Kimwipe. If oily, place a few
drops of 70% ethyl alcohol onto the Kimwipe and gently wipe the cover
slip and bottom of slide. Never place alcohol directly onto a prepared
slide.
2. Place the slide down on the front of the stage with the label facing up and in
position to be read. Open the spring stage clip by pulling the clip arm out.
While keeping the slide flat on the stage, maneuver the slide to rest firmly
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IRSC Biological Sciences Department
against the L-shaped guide of the slide holder. Slowly release the stage
clip so that it rests against the corner of the slide (NOT on top of the
slide).
3. With the scanning objective in position, use the coarse adjustment knob to
move the stage up until it stops. Look from the side of your scope to
visually confirm that the objective will not touch the cover slip on top of the
slide.
4. Align the cover slip of the slide over the opening in the stage using the
graduated mechanical stage control knobs located below and at the left
side of stage.
5. Turn on the light to sufficient intensity to produce a WHITE background (not
yellow). Note that the condenser is in the full up position. Locate the
condenser height control knob forward from course / fine adjustment
knobs.
6. Adjust for individual eye differences:
A. Viewing through the right eye piece (left eye closed), adjust the coarse
adjustment knob away from you until the image is clear. This will
involve lowering the stage no more than about one-fourth of an inch.
An additional slight adjustment (no more than two revolutions) of the
fine adjustment knob may be needed to bring the specimen into BEST
focus.
B. Then viewing with the left eye (right eye closed) through the left ocular
use the diopter adjustment or zoom feature at the base of this left
ocular to bring the specimen into best focus for your left eye.
C. Viewing with both eyes open, adjust the interpupillary distance by
grasping the eye pieces plate and moving the eye pieces closer or
farther apart. You should see ONE circular field of light. You may
also need to adjust the distance you hold your head from the oculars.
Now the slide is in best focus for both eyes.
7. Use the iris diaphragm lever to adjust the amount of light striking your
specimen. More light will be needed for preserved and stained slides
and at higher magnifications. Less light is required for thin
preparations and unstained slides. Remember the condenser remains
in its full uppermost position when storing the microscope.
Moving to next higher magnification power (specimen is in best focus under
scanning):
1. Center the specimen to be examined further in the CENTER of the field of
view. These microscopes are parfocal. This means that the specimen
is focus at the center of the field of view will be in partial focus as the
next power.
2. While observing the movement of the objectives from the side grasp the
revolving nosepiece and rotate it to the next power (low power – yellow
band).
3. Only minor adjustment with the coarse adjustment (for scanning and lowpower objectives ONLY), then fine adjustment (no more than 2
revolutions) if needed.
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
4. When moving to high power, repeat steps #1 and #2, but in #3 you may use
ONLY fine adjustment knob with high power objective. Watch that it will
not touch.
5. To use the 100X objective, you need to add a drop of immersion oil on the
slide. This technique will be more fully describe on the next page.
After observations have been completed:
1. Move the revolving nosepiece to low and then to scanning. Do not drag the
oil immersion objective (longest objective) across the cover slip or you will
scratch the objective lens!
2. Open the spring stage clip and slide the microscope slide out to the forward
edge of the stage.
3. Return the clean slide to where you obtained it (your slide box or the side
counter).
4. Do not lower the stage or turn off the light if you have another slide to view.
5. View other slides that are assigned.
6. After last slide of the day is finished, prepare the microscope for storage as
outlined below.
Storage of your microscope in cabinets:
1. Scanning objective (4X with red band) in position!
2. Power switch off (before unplugging the microscope)!
3. NO slide on the stage!
4. All lenses and the stage must be clean!
5. Graduated mechanical stage centered!
6. Stage in the full down position! (Do not lower the condenser!)
7. Cord wrapped around the cord holder! (Cord bound with a rubber band in
SLW!)
8. Plastic dust cover is on! (In SLW, DO NOT store cord up inside cover!!)
9. The microscope sits above its number on the cabinet shelf!
Oil immersion techniques (for A&P II, Biology II, & Microbiology Labs ONLY):
1. Focus the slide as before under the scanning, low power, and high power
objectives. Now the stage and lighting are set for the best resolution of the
specimen.
2. DO NOT lower the stage!
3. Rotate the revolving nosepiece back the way you came to high (back to low,
then to scanning). Do not drag the long oil immersion objective over the
cover slip.
4. Place a drop of immersion oil (from your drawer) on the cover slip where the
light is passing through the slide. Be careful not to allow any oil to flow
over the edge of the slide onto the condenser lens or onto the stage.
5. Looking from the side of your scope, visually confirm that the objective will not
touch the cover slip of the slide. Rotate the revolving nosepiece
DIRECTLY from scanning (4X) objective to the 100X objective. You can
see the oil come into contact with the 100X objective.
6. Focus using the fine adjustment knob.
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IRSC Biological Sciences Department
7. You may need more light. Move the iris diaphragm lever to allow more light
on the slide.
8. After study of specimen is complete, turn the revolving nosepiece DIRECTLY
from 100X objective to the 4X objective. This avoids bringing other long
lenses in contact with the oil.
9. Open the spring stage clip and remove slide forward toward the edge of the
stage.
10. CLEAN the slide – Remove most of the oil by blotting cover slip with a
Kimwipe. Add some 70% ethyl alcohol on a clean Kimwipe and remove
any remaining oily residue. Return clean slide to where you obtained it
(your slide box or side counter).
11. CLEAN the 100X objective if you are through using oil for this lab session.
Blot (DO NOT RUB) the objective with a clean Kimwipe. Use lens paper
to polish the 100X lens until no oily residue is observed on the Kimwipe.
Use lens paper to check other objectives to be sure no oil is on them.
***Never use any liquid to clean your microscope lenses. ***
Using phase contrast optics:
This type of microscopy is used when live, unstained specimens are to be viewed.
1. Focus the specimen as you have been instructed above on 4X, 10X, and 40X.
2. When you are in best focus on high power (40X objective), push the phase
ring holder into the path of light. Make sure the condenser is raised to its
highest position. Also, make sure the lever controlling the amount of light
entering the condenser is fully open. You may also have to turn the light
source on full.
3. Only the high power (40X) objective may be used with the phase contrast
optics.
Using dark field optics:
This type of microscopy is used when studying diatoms and algae.
1. Obtain a dark field adapter. Your lab instructor who will show you where to
obtain the adapter numbered for your microscope.
2. Remove the blue filter and snap it onto the bottom of the adapter.
3. Snap the top of the adapter to the bottom of the condenser.
4. Focus normally. Your best resolution will be at low power. Note the different
colors.
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
Measurement of a specimen using the microscope:
A. Use the ocular micrometer – the small “ruler” in the right eyepiece. For small
specimens that will fit under the ocular micrometer, position ocular
micrometer over specimen. Move the slide on stage to position the
specimen. You can move the ocular micrometer by rotating the ocular. The
size of the specimen can be determined by multiplying the number of ocular
micrometer spaces covered by the specimen by the conversion factor for
that objective as given in the following table:
OBJECTIVE:
Scanning
Low-power
High-power
Oil immersion
OCULAR MICROMETER CONVERSION FACTOR:
25 microns (micrometers)
10 microns
2.5 microns
1.0 microns
B. Use the graduated mechanical stage markings.
For larger specimens too large to fit in the space of the 100 units on the
ocular micrometer, follow these steps:
1. Place the zero line of ocular micrometer at the anterior end of the
specimen. You can move the ocular micrometer by rotating the ocular.
2. Record the coordinates to the nearest tenth from the graduated
mechanical stage axes.
3. View through the ocular micrometer, move the zero line of the ocular
micrometer to the posterior end of the specimen.
4. Record the new coordinates to the nearest tenth.
5. Calculate the difference between the coordinates. The stage is marked
in graduations of one millimeter.
6. Convert you answer in millimeters to microns by multiplying mm by
1,000.
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IRSC Biological Sciences Department
Plant Cell Model Key
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IRSC Biological Sciences Department
Animal Cell Model Key
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
Introduction to Cells, pH and DNA
Lab Activities:
Animal and Plant Cells – Exercise 4.2, p. 43-46 (Learn the eukaryotic cell
organelles’ structures and functions from models);
2. pH – Exercise 4.5, p. 54-55;
3. DNA Structure – Exercise 11.1, p. 133-135 (Nucleotides, Complementary H-bonds,
Double helix, etc.);
4. DNA Isolation – Exercise 11.4, p. 142 as modified below.
1.
Isolation of DNA:
Materials needed:
*Banana (1per lab class)
*Blender
*15% NaCl solution (approx. 200mL per banana)
*250mL beaker
*Dawn dish detergent
*Cheese cloth
*Large funnel
*500mL Erlenmeyer flask
*Meat tenderizer
*Ice bucket and ice
*Ice cold ethanol (inside ice bucket)
*Test tube rack
*(8) Test tubes (1 for each group)
*(8) Glass rods or Inoculating loops (1 for each group)
Procedures:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Peel a ripe banana, break it into chunks, and place it in a blender.
Cover the banana pieces with 15% NaCl solution (approx. 200mL).
Add 2 drops of Dawn dish detergent before blending.
Blend the banana pieces, 3 – 4 short bursts.
Pour the blended mixture into a funnel lined with four layers of cheese cloth.
Catch the filtrate in a glass flask.
Add a pinch of meat tenderizer to the filtrate and mix.
Each group is to fill a standard test tube half-full with the mix and let it sit
(incubate) for 15-20 minutes at room temperature.
Tilt the test tube to a 450 angle. Slowly add ice cold ethanol to the tubes by
running it down the side of the tube.
DNA will appear as a whitish mass in the ethanol.
If the DNA does not appear immediately, slowly stir the interface with the glass
stir rod (or metal inoculating loop).
Insert the glass stir rod/inoculating loop into the interface in the test tube and
rotate the rod/loop in one direction to “spool” the DNA onto the rod/loop.
DNA will adhere to the rod/loop and can be spooled by rotating the rod/loop.
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MEASURING THE RATE OF OSMOSIS
In this experiment, dialysis tubing will be used that will represent differential
permeable membranes – water can pass through but sugar cannot.
MATERIALS NEEDED PER GROUP (4 GROUPS TOTAL / LAB CLASS):
(4) 250mL beakers
(1) triple-beam balance
(1) 50mL graduated cylinder
15mL 20% sucrose
(1) small funnel
15mL 40% sucrose
(4) soaked dialysis bags (20cm strips) 15mL 60% sucrose
(4) strings to tie bags at top
China marker
(1) pair scissors (to cut strings)
Tap water
Each group of students will use four dialysis bags, which will function as artificial,
differential permeable membranes. Each bag should be tied at one end by folding the
end over and tying with a string. Make sure it is leak-proof.
Carefully insert a small funnel into the top of the bag. Fill these bags as follows:
Bag 1: 15mL of tap water
Bag 2: 15mL of 20% sucrose solution
Bag 3: 15mL of 40% sucrose solution
Bag 4: 15mL of 60% sucrose solution
*Bag 5 (a demonstration bag): 15mL of tap water (at instructor’s desk);
SETUP ONLY ONE Bag 5 & Beaker 5 for each lab class.*
As each bag is filled, remove the air by gently squeezing the bottom end of the
bag to bring the liquid to the top of it. Press the sides of the bag together so that air
does not reenter. Fold the end of the bag over about 2 inches (5cm), and tie securely
with a string. Weigh each bag separately to the nearest 0.1g, and record each bag’s
mass in the table below at zero time, (0).
Time (in
minutes):
0
15
30
45
60
Bag 1
Mass of Bags (in grams):
Bag 2
Bag 3
Bag 4
Bag 5
Place Bags 1, 2, 3 and 4 in separate 250mL beakers of water. *Bag 5 (the demo
bag) will go into a 250mL beaker of 60% sucrose solution at the instructor’s desk.*
At 15-minute intervals remove the bags from the beakers, carefully wipe off all
excess water, and weigh each bag separately. Record the data in the table above.
CLEAN UP: Remove string from one end of bag without cutting the bag. Empty
contents of bags, rinse bags with tap water, and return used dialysis bags back into
designated specimen dish filled with tap water. Wash glassware with soap and water.
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Final rinse is with Ethyl alcohol (Ethanol) for quick dry of containers too small to
dry with paper towels (graduated cylinders and funnel necks). CAREFULLY WIPE
SUGAR WATER OFF ALL PARTS OF THE BALANCES!!!! Wipe off mats too.
Plot the changes in mass of each bag against time (use graph provided below).
What relationship is there between the concentration of sucrose (the concentration
gradient) and the rate of osmosis? Explain.
Bag 1 ( ■ ): 15mL of tap water
Bag 2 ( □ ): 15mL of 20% sucrose solution
Bag 3 ( ● ): 15mL of 40% sucrose solution
Bag 4 ( ○ ): 15mL of 60% sucrose solution
Bag 5 ( ▲ ): 15mL of tap water
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Cellular Respiration - Aerobic Respiration Set-up:
1. Construct respirometers: Obtain 3 large test tubes, in addition to three individual,
separate stoppers with calibrated pipettes attached. There is cotton in the bottom
of each tube saturated with 15% potassium hydroxide, (KOH), which absorbs CO2.
A second (non-soaked) piece of cotton has been added to the top of the KOHsoaked cotton. Caution – KOH is caustic!
2. Obtain a 100 mL graduated cylinder, and add 50mL of water. Drop in 25 germinating
peas, and measure the amount of water displaced (that is, how much the water
rises above 50mL). Record this number here: ____ mL. Remove the water and
germinating peas. Dry the peas on a paper towel.
3. To Tube 1, add the 25 towel blotted germinating peas. Insert the stopper fitted with a
calibrated pipette. Place a large donut weight around the tube.
4. Again add 50mL of water to the 100mL graduated cylinder and this time drop in 25
non-germinating peas. Add glass beads until the same amount of water is
displaced as in step 2. Remove the water, peas and glass beads. Dry the glass
beads and peas on a paper towel.
5. To Tube 2, add the 25 towel blotted non-germinating peas and glass beads. Insert
the stopper fitted with a calibrated pipette. Place a large donut weight around the
tube.
6. Once more, add 50mL of water to the 100mL graduated cylinder. Then, drop in glass
beads until the same amount of water is displaced as in step 2. Remove the water
and glass beads. Dry the beads on a paper towel.
7. To Tube 3, add the dried glass beads. Insert the stopper fitted with a calibrated
pipette. Place a large donut weight around the tube.
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8. Lay the respirometers in the water bath, with the pipettes resting on the test tube
rack. Wait 7 minutes so that the temperature of the tubes and the water bath is the
same.
9. Shift the respirometers on the rack so that the PIPETTE TIPS are completely
submerged in water. DO NOT ALLOW WATER TO ENTER TUBES!!!!
Water will enter the PIPETTES for a short distance and then stop. Record this
initial position of the water drop to the nearest 0.01mL on the table below. — If
water continues to move into a pipette, check for leaks in the respirometer. Quickly
arrange the pipettes so that they can be easily read through the water at the
beginning of the experiment. Once set, DO NOT MOVE the pipettes or tubes.
Keep your hands out of the water bath once the experiment has started.
10. Complete the data table below: A) Wait 10 minutes, and then record in the data
table any change in the position of the marker drop. B) Wait 10 minutes (20
minutes after start), and then record in the data table any change in the position
of the marker drop. C) Then record the net change of each tube. Calculate by
subtracting the tube's 20 minute reading from the initial reading for each tube.
11. Did the marker drop change in Tube 3 (glass beads)? _______ If so, by how
much? _______ Enter this number in the "Correct" column below and use this
number to correct the net change you observed in Tubes 1 and 2. This is a
correction for any change in volume due to atmospheric pressure changes or
temperature changes.
Cellular Respiration Data
Tube
Content
1
Peas
2
Peas +
Beads
3
Beads
Initial
Reading
After 10
minutes
After 20
minutes
17
Net
Change
Correct
Correct
Net
Change
GENERAL BIOLOGY I
IRSC Biological Sciences Department
FERMENTATION – Anaerobic Respiration Set-up:
1. Tube 1: In a 50mL beaker, mix 6mL of suspended (well-stirred) yeast solution
with 12mL of 2% Fructose (sugar) solution. Re-suspend (mix well) yeast solution
each time you add it to a fermentation (gooseneck) tube. Pour yeast mixture into
a labeled fermentation tube for the test solution, place your thumb over opening
and invert it once to fill the calibrated portion of the tube.
2. Tube 2: In a 50mL beaker, mix 6mL of suspended (well-stirred) yeast solution
with 12mL of 2% Glucose (sugar) solution. Re-suspend (mix well) yeast solution
each time you add it to a fermentation (gooseneck) tube. Pour yeast mixture into
a labeled fermentation tube for the test solution, place your thumb over opening
and invert it once to fill the calibrated portion of the tube.
3. Tube 3: In a 50mL beaker, mix 6mL of suspended (well-stirred) yeast solution
with 12mL of 2% Sucrose (sugar) solution. Re-suspend (mix well) yeast solution
each time you add it to a fermentation (gooseneck) tube. Pour yeast mixture into
a labeled fermentation tube for the test solution, place your thumb over opening
and invert it once to fill the calibrated portion of the tube.
4. Tube 4: In a 50mL beaker, mix 6mL of suspended (well-stirred) yeast solution
with 12mL of DI (de-ionized) Water. Re-suspend (mix well) yeast solution each
time you add it to a fermentation (gooseneck) tube. Pour yeast mixture into a
labeled fermentation tube for the test solution, place your thumb over opening
and invert it once to fill the calibrated portion of the tube.
5. Carefully carry the four prepared fermentation tubes to the water bath. Place the
fermentation tube in a 38º C temperature water bath.
6. Allow the tubes to incubate; stop the incubation when appropriate (approximately
3 - 4mL of CO2, or about 30 minutes).
7. At the end of the incubation period, measure the final volume of CO 2 in each tube
and record the volume. Use volume instead of height; set initial volume equal to
zero.
18
GENERAL BIOLOGY I
IRSC Biological Sciences Department
BSC2010L GENETICS PROBLEMS
Part 1 Derivation of gametes:
Gametes are haploid. Each gamete normally will have only one copy of the gene. A
circle is used to indicate each haploid gamete. Check that there is only one letter for
each trait in the circle.
It is possible to determine expected ratios, numbers and types of gametes when the
parental genotype is known.
Example: Determine the expected ratios and types of gametes resulting from :
1)
A heterozygous individual, Bb
One-half the gametes will be B
One-half the gametes will carry b
Ratio is 1:1
2)
A genotype of AaBb
AB : Ab : aB : ab
These 4 kinds of gametes are in a
ratio of 1 : 1 : 1 : 1
3)
Give the expected number of
different gametes only AaBbCCDd
# types = 2n ; Where n = the number
of heterozygous gene pairs
23 = 8 (a total of 8 different
combinations can result)
Part 1 Problems:
1. How many different gametes would you expect from a man who is homozygous
for brown eyes, BB?
2. What are the gametes of a person with genotype AABb? (Hint: there are two;
remember that in each gamete you need one of each letter.)
3. A. How many gametes are produced from each oögonium?
B. How many gametes are produced from each spermatogonium?
4. Give the number of expected types of gametes from the following genotype
(Remember: # types = 2n (n = number of heterozygous gene pairs in the example):
A. AaBbCC
B. DdEdFfGgHH
C. A person with all chromosomes in heterozygous pairs (hint: how many
chromosomes do humans have?
19
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 2 Monohybrid Inheritance:
Crosses of this type involve only a single pair of genes (not traits).
Example: In fruit flies (Drosophila melanogaster), Red eye color is dominant over sepia
eyes. By crossing a heterozygous Red-eyed male with a heterozygous Red-eyed
female fly, 60 offspring result. How many would you expect to be Red-eyed and how
many sepia-eyed?
1) Set up your key: Let R = Red and r = sepia
2) Determine the genotypes of the parents of Rr (♂=male) and Rr
(♀=female).
3) Determine the gametes (sperm) produced by the male: ½ R and ½ r
4) Determine the gametes (eggs) produced by the female: ½ R and ½ r
5) Derive all possible combinations for the gametes:
Arrange the genes on a: (A) checkerboard or Punnett Square OR
(B) use the fractional method (fool-proof)
6) Record the genotypic results and phenotypic descriptions
(A) Punnett Square Method for monohybrid crosses only:
Parents: Rr (♂) x Rr (♀)
EGGS
SPERM
(B)
R
r
R
RR
Rr
r
Rr
rr
Genotypic results: ¼ RR, 2/4 Rr, ¼ rr
genotypic ratio is 1 : 2 : 1
Phenotypic results: ¾ Red, ¼ sepia
phenotypic Rratio is 3 : 1
¾ of 60 offspring = 45 Red
¼ of 60 offspring = 15 sepia
Fractional Method
Parents: Rr (♂) x Rr (♀)
One-half of the male gametes will be R and one-half r . Likewise the
female produces two types of gametes, ½ R and ½ r . Use algebraic
multiplication to determine all possible combinations of these gametes:
¾ of 60 offspring = 45 red
♂ gametes ♀ gametes offspring
½R 
¼ RR
x 60
=
15 RR flies
¼ of 60 offspring = 15 white
½ R

½R 
¼ rR ½ Rr
=
+30 Rr flies = 45 Red
½R 
¼ rR 
½ r
½r 
¼ rr x 60
=
15 rr flies = 15 sepia
Genotypic results: ¼ RR, 2/4 Rr, ¼ rr
Genotypic ratio is 1 : 2 : 1
Phenotypic results: ¾ Red, ¼ sepia
Phenotypic ratio is 3 : 1
¾ of 60 offspring = 45 Red
¼ of 60 offspring = 15 sepia
20
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 2 Problems:
In humans, albinism controlled by a single recessive allele c, and normal pigmentation
is controlled by the dominant allele, C. Use this information for questions 5 – 8.
5.
What would be the phenotype of the following genotypes?
(A) CC _________ (B) Cc __________ (C) cc __________
6.
Suppose CC mates with cc, what would be the expected phenotypic ratio and
genotypic ratio of the offspring? Do a Punnett square.
7.
Suppose Cc mates with cc, what would be the expected phenotypes and
genotypes, and their relative frequency, if many children were produced?
Suppose two albino children had been produced, what is the chance the next will
be albino?
8.
A man and woman plan to marry and wish to know the probability of their having
any albino children. What would you tell them if both are normally pigmented, but
each has one albino parent?
9.
Phenylketonuria (PKU) is a heritable condition in humans involving inability to
metabolize the amino acid phenylalanine because of lack of a certain enzyme. If
not diagnosed and treated very shortly after birth, children affected by PKU
develop severe mental retardation, and usually do not reproduce. Almost all PKU
children, therefore, are born to parents who are not affected by PKU (but are
carriers for the disease).
A. Is the gene responsible for phenylketonuria (PKU) completely
dominant, incompletely dominant, or recessive?
B. What kind of child would result from the mating of two parents with
PKU?
10.
In humans, earlobes can be attached or unattached (or free). A man with
attached earlobes marries a woman with free earlobes. All of their children have
free earlobes. One son (with free earlobes) marries, and of his many children,
half have free earlobes and half have attached earlobes.
A. What is the phenotype of the man’s wife?
B. Are attached earlobes dominant or recessive?
11.
In dogs, wire hair is due to a dominant allele (gene), smooth hair to its recessive
allele. Two wire-haired dogs produce a male pup which is wire-haired. To find
out most quickly whether he carries the gene for smooth hair, he should be
mated to what kind of female?
21
GENERAL BIOLOGY I
IRSC Biological Sciences Department
12.
Recall in fruit flies red eyes is dominant over sepia eyes.
A. Do a Punnett Square to show the cross of:
RR x rr
(P generation)
(Offspring are F1 generation)
B. Now cross two F1 generations to see genotypes F2 generation
Part 3 Dihybrid Inheritance:
In dihybrid crosses, two pairs of genes are involved. In all dihybrid problems (and
trihybrid) use the fractional method or the Punnett Square method for all possible
combinations of genes per gamete.
Example: AaRr x AaRr
1)
Treat each allele as if the cross were a monohybrid.
Aa x Aa 
¼ AA : 2/4 Aa : ¼ aa
Rr x Rr 
¼ RR : 2/4 Rr : ¼ rr
2)
Now cross each allele independently with the others.
1/
¼ RR

16 AARR
2
2/
¼ AA
/4 Rr

16 AARr
1
¼ rr

/16 AArr



2/
2/4 Aa
¼ RR
2/ Rr
4
¼ rr



1/
¼ aa
¼ RR
2/ Rr
4
¼ rr
16
4
/16
2/
16
AaRR
AaRr
Aarr
aaRR
16 aaRr
1/
16 aarr
16
2/
3) Report genotypic results: ratio: 1:2:1:2:4:2:1:2:1
Report phenotypic results by additive law of probability. Ratio is 9:3:3:1
ALTERNATE METHOD FOR PHENOTYPIC RESULTS ONLY
If only the phenotype is asked for in the problem then use the characteristic
monohybrid phenotypic ratio. (3:1 in above problem)
**Note that a blank( _ ) is drawn for the second allele if it does not control expression of
the trait.
¾ A_
 9/16 A_R_
 3/16 A_rr
¾ R_
¼ rr
¾ R_
 3/16 aaR_
¼ rr
 1/16 aarr
Report phenotypic results: 9:3:3:1
¼ aa
22
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 3 Problems:
13. In cattle, Polled, (P), (hornless) condition is dominant over horned (p) and Black
(B) is dominant over yellow (b). What will be the genotype and phenotype of the
F1 in a cross between a homozygous Polled, homozygous Black bull and a
horned, yellow cow? Do a Punnett square.
(P generation: PPBB x ppbb)
14.
A solid-colored, Short-haired female rabbit (ssLL) is mated to a Spotted-colored,
long-haired male (SSll). How many offspring will be expected to be Spotted with
long hair? How many offspring will be expected to be solid-colored with Short
hair?
15.
In some-dogs, Barking when trailing (B) is due to a dominant allele; other dogs
do not bark when trailing (b). Also in dogs, Erect ears (E) are dominant over
drooping ears (e). What is the phenotypic ratio of offspring when you cross two
heterozygous dogs (BbEe x BbEe)? Do a Punnett square.
BE
bE
Be
be
Barking, Erect ears: _____ Barking, drooping ears: _____
no bark, Erect ears:_____ no bark, drooping ears:_____
Part 4 Incomplete Dominance:
In this type of inheritance neither allele is completely dominant over the other. For this
reason the heterozygous individual will show a phenotype that is intermediate between
the phenotypes of the two possible homozygous types. To denote incomplete
dominance use the prime notation. The alleles should read A and A'. The use of
capital letters for both alleles indicates that neither is dominant.
Example:
In snapdragons, red flower color (R) is incompletely dominant over white flowers (R').
The heterozygote RR' will have pink flowers. In a cross between two pink-flowered
plants, determine the parental genotypes, show what gametes are produced, and show
the expected phenotypic ratios among the offspring.
1) Set up your key using prime notation: RR = red, RR’ = pink,
R’R’ = white.
2) Determine the genotypes of parents: RR' x RR'
23
GENERAL BIOLOGY I
IRSC Biological Sciences Department
3) If it’s a monohybrid cross, you can use the fractional method with
gametes. (If dihybrid, use the results of this example and solve it as a
dihybrid example.)
male gametes:
½R
female gametes:
½R

½ R'

½R

½ R'
½ R'

genotypic results: ¼ RR, 2/4 RR’, ¼ R’R’
phenotypic results: ¼ red, 2/4 pink, ¼ white
offspring:
¼ RR
¼ RR' 
¼ R'R 
¼ R'R'
phenotype:
red
½
pink
white
16.
Predict the results of a cross between a red-flowered snapdragon and a
white-flowered one. Do a Punnett square.
17.
In snapdragons red flowers (R) are incompletely dominant over white (R') with
pink flowers in the heterozygous individuals. Broad leaves (L) are incompletely
dominant over narrow leaves (L') and the heterozygotes have medium-wide
leaves. Predict the proportions of offspring from the following crosses:
A) Pink-flowered Medium-leafed x Pink-flowered Medium-leafed
B) Pink-flowered Broad-leaved x Pink-flowered Medium-leafed
Part 5 Sex Linkage:
Certain traits are carried by the X chromosomes. In all problems involving sex linkage,
report the results for the two sexes separately. There are two standard notations for
sex-linked traits. The preferred one involves the use of the X and Y chromosomes with
superscripts at the X chromosomes. The superscripts are like monohybrid notation.
Example: XCXc
x
XCY
A second notation replaces the X chromosome with the standard monohybrid
notation and uses the Y chromosome as an allele. Careful, this method can be
troublesome if your memory of the genetic mechanism is not clear.
Example: Cc x CY.
Example:
Normal vision in man is dominant to color blindness and the alleles are on the sex
chromosome. A normal male whose father was color blind marries a color blind woman.
What would be the chance of their sons and daughters being color blind?
1) Set up your key: Let XC = normal; Xc = color blind
2) Determine the genotypes of the parents:
Male is XCY
Possible gametes are XC and Y
Female is XcXc
Only gamete is Xc.
24
GENERAL BIOLOGY I
IRSC Biological Sciences Department
3) Use the fractional method to solve this monohybrid cross:
Female gametes:
Male gametes:
Offspring:
Phenotypes:
C
C c
1/2 X

1/2 X X ♀ Normal (carriers)
c
X
1/2 Y

1/2 XcY
♂Color blind
4) Sex-linked problems must have results stated by sex.
None of the daughters would be color blind, but all would be
heterozygous for the trait; all sons would be color blind.
Part 5 Problems:
18.
A boy, whose parents and grandparents had normal vision, is color blind. Give
the genotypes of his mother and his maternal grandparents.
19.
A woman with defective tooth enamel (autosomal recessive) and normal color
vision, (X-linked) who had a color blind father with normal tooth enamel and a
mother with normal vision and defective tooth enamel, marries a color blind first
cousin with normal tooth enamel who had a father with defective tooth enamel.
What is the probability of their having a child with normal tooth enamel and color
blindness?
20.
21.
Do a Punnett square.
In man, one type of night blindness, in which the individual sees normally in
bright light but very poorly in dim light, shows recessive sex-linked inheritance:
A woman with normal sight, whose father was night blind, marries a man with
night blindness. What are the types and proportions of offspring to be
expected?
Nystagmus is a condition in man characterized by involuntary rolling of the
eyeballs. The gene for this condition is incompletely dominant and sex-linked.
Three phenotypes are possible: Normal, slight rolling, severe rolling. A woman
who exhibits slight nystagmus and a normal man are considering marriage and
ask a geneticist what the chance is that their children will be affected. What
would the geneticist tell them?
Part 6 Multiple Alleles:
The following problems are based on the inheritance of the ABo blood groups in
humans. There are three alleles: IA, IB, and Io. The IA and IB are co-dominant over the
recessive Io. Genotypes for each ABo blood group are given as follows:
IAIA and IAIo = blood group A
IBIB and IBIo = blood group B
IAIB = blood group AB
IoIo = blood group o.
*For your information: the Rh blood grouping system is inherited as simple dominance,
therefore Dominant = Rh+ and recessive = rh-.
25
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 6 Problems:
22.
List all of the possible blood groups that may occur in the children of each of the
following blood group crosses:
A)
AB x o
B)
A x AB
C)
BxB
D)
AxB
E)
Axo
23.
A)
B)
Could a child of blood group (o) be born to parents of whom are of
blood group A?
Could a child of blood group AB be born to these parents?
24.
Suppose a father of blood group A and a mother of blood group B have a child
of blood group (o). What groups are possible in their subsequent children?
25.
In blood types, Rh+ (Rh positive) is dominant over rh- (rh negative). A couple
believes they have brought the wrong baby home from the hospital. The wife is
o+ (“o” positive), the husband is B+ (B positive), and the child is o- (“o” negative).
Could the child be theirs?
26.
In a court action, a man claims that some of the six children born to his wife are
not his. Blood tests give the following information:
Husband: o+
Children:
1) A+
2) o3) AWife: A+
4) o+
5) AB+
6) BCould all these children belong to the husband? Explain
why or why not.
26
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 7 Chi-Square:
Chi-Square Test for the “goodness of fit” of experimental data with the theoretical expected
calculated using genetic hypotheses.
Solve this problem as you would in earlier examples in this set of genetics problems.
You have to make your genetic hypothesis as to the mechanism of inheritance.
1.) _____ Set up your key to notation.
2.) _____ Determine the genotypes of the parents.
3.) _____ Consider the type of inheritance that you think (hypothesis) may be
operating for each and every trait in the experiment, such as
complete dominance, incomplete dominance, sex-linkage, etc.
4.) _____ Solve the genetics problem to determine the expected outcomes
from this cross. Use fractions or percentages for each expected
phenotype.
5.) _____ Enter the phenotypes of the types of offspring produced.
6.) _____ Record the data given in the problem or obtained from lab counts.
7.) _____ Total the number of observations made or given.
8.) _____ Multiply the theoretical expected fraction or percentage times the
total number of offspring observed to determine the theoretical
expected value.
9.) _____ Complete the columns below as indicated by the headers.
Expected:
Difference:
(d)2
(e)
(d)
(d)2
e
__________ __________ _________
_________
__________ __________ _________
_________
__________ __________ _________
_________
__________ __________ _________
_________
Expected
Total =
ratio (x) total =
_________
___________
10.) _____Total the final column to give the chi-square value.
11.) _____Look up the Chi-Square value from the table in your lab manual.
The first column in the table is the degrees of freedom, (C), column.
This is determined by taking the number of phenotypic classes and
subtracting one. For example, if there are four phenotypes, then
the degrees of freedom, (C), will be
4 – 1 = 3. Therefore, you will look for the chi square total value in
the third row of the table.
12.) ____ Note the header of the column in the Chi-Square table where you
find the value closest to your total Chi-Square value. This is your p
value.
13.) ____ If your p value is greater than 0.10, then your hypothesis concerning
the method of inheritance is supported by the experimental data.
However, if your p value is 0.01 or less, then your hypothesis is not
supported by the data. This may mean that there is an error in the
experiment or that some other genetic mechanism is in control of
inheritance of that trait.
Phenotypic
Class:
__________
__________
__________
__________
Observed:
(o)
__________
__________
__________
__________
Total =
__________
27
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Part 7 Problems:
27.
The flowers of four o'clock plants may be red, pink, or white. Reds crossed to whites
produced only pink offspring. When pinks were crossed, they produced 113 red, 129
white, and 242 pink. It is thought that these colors are due to co-dominant alleles. Is this
hypothesis acceptable on the basis of a chi-square test?
28.
In corn, Purple kernels (P) are dominant over yellow kernels (p) and Smooth kernels (S)
are dominant over wrinkled kernels (s). Cross two heterozygotes PpSs x PpSs,
A. Do a dihybrid Punnett square.
Kernels have been counted on an ear of corn, the following data was collected:
 Purple, Smooth = 195
 Purple, wrinkled = 71
 yellow, Smooth = 80
 yellow, wrinkled = 25
B. Do these numbers follow the 9:3:3:1 ratio? Perform a Chi-square
analysis (use table on next page):
Phenotype:
Purple, smooth
Purple, wrinkled
Yellow, smooth
Yellow, wrinkled
Observed
(o):
195
71
80
25
Expected
(e):
9 x 23.2 =
3 x 23.2 =
3 x 23.2 =
1 x 23.2 =
Difference
(d):
d2:
d2/e:
X2=
Total = ____
371/16 = _____
After you get x2, look at the Chi-square table in your book to see if the 9:3:3:1 hypothesis is supported or
not supported. C - 1 = 3 because we have 4 phenotypes in this example, thus (C) = 4, so 4 – 1 = 3.
28
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Answers to the Genetics Problems
1.
2.
3.
4.
5.
6.
7.
8.
18.
19.
one kind, B
1 AB : 1 Ab
(A) 1, (B) 4
(A) 22=4, (B) 24=16, (C) 223
(A) normal, (B) normal, (C) albino
All (100%) normal (Cc), (Punnett square…)
1/2 Cc (normal), 1/2 cc (albino); 50:50
phenotypic: 3/4 (or 75%) normal, 1/4 (or 25%) albino
genotypic: 1/4 CC (normal, 25%) + 2/4 Cc (or one half, normal, 50%) = 75%,
1/4 cc (albino, 25%)
(A) recessive, (B) PKU
(A) attached, (B) recessive
smooth hair female
(A) All are Rr, (B) 1 RR, 2 Rr, 1rr, (Punnett squares…)
All are Polled and Black (PpBb), (Punnett square…)
None, none (all are spotted, all are short-haired)
9 Barking, Erect ears:3 Barking, drooping ears:3 no bark, Erect ears:1 no bark,
drooping, 9:3:3:1 (Punnett square…)
pink, (Punnett square…)
(A) 1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1
(B) 1 : 1 : 2 : 2 : 1 : 1 :
mother: XCXc, grandparents: XCY, XCXc
25%, (Punnett square)
20.
of the females -
9.
10.
11.
12.
13.
14.
15.
16.
17.
21.
22.
23.
24.
25.
26.
27.
28.
1/2 are normal (& carriers)
1/2 are night blind
of the males 1/2 normal
1/2 night blind
daughters: 1/2 normal, 1/2 slight rolling
sons: 1/2 normal, 1/2 with nystagmus
(A) A, B
(B) A, B, AB
(C) B, o
(D) A, B, AB, o
(A) yes,
(B) no
A, B, AB, o
yes, it is possible
no, not children #5 and #6
x2 = 1, yes, hypothesis is supported (differences are insignificant)
(A) 9:3:3:1 – a dihybrid Punnett square,
(B) Hypothesis is supported (differences are insignificant)
Phenotype:
Purple, smooth
Purple, wrinkled
Yellow, smooth
Yellow, wrinkled
Observed (o):
Expected (e):
195
9 x 23.2=209
71
3 x 23.2=70
80
3 x 23.2=70
25
1 x 23.2=23
Total 371
371/16=23.2
Difference (d):
14
1
10
2
29
d2:
196
1
100
4
(E) A, o
d2/e:
0.94
0.014
1.43
0.174
x2= 2.56
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Albino Tobacco – Chi-Square Test
A self-fertilized green tobacco plant was discovered to have many white (albino)
seedlings among its offspring. By analysis of offspring resulting from such a self-fertilization, you
will determine the pattern of inheritance for the mutation and the genetic make-up of the parent
plant for this characteristic.
GERMINATION: About 50 seeds were placed in a box on soaked paper for 10+ days.
OBSERVATIONS: Count and record the number for each phenotype (green or albino) of
tobacco seedlings. Each member of the lab team should count at least one box.
DATA INTERPRETATION:
1) Do you think this gene for albinism is dominant or recessive? _________________
2) Roughly what appears to be the ratio of green to albino? ___:____
DATA ANALYSIS: Perform the Chi-Square test to determine how well your
experimental results correspond to theoretical predictions. Check Chi-square procedures in
Genetics Problems handout in this General Biology I Lab Student Supplemental Packet.
Determine the p value from table below: p = _____
Does your data fit your theoretical expectation? _____
If A represents the gene for chlorophyll and a represents the gene for albinism, what was the
genotype of the parent plant of these seedlings? ___________
30
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Monohybrid corn – Group/Student data (one ear of corn):
Phenotypic
Classes
Observed
(o)
Expected Result
(e)
Total # =
(Expected ratio X)
Total #
Difference
(d)
d²
d² / e
Purple
Yellow
Total =
Monohybrid corn – Class data (all ears of corn counted & totals combined):
Phenotypic
Classes
Observed
(o)
Expected Result
(e)
Total # =
(Expected ratio X)
Total #
Difference
(d)
d²
d² / e
Purple
Yellow
Total =
Dihybrid corn – Group/Student data (one ear of corn):
Phenotypic Classes
Observed (o)
Expected Result
(e)
Total # =
(Expected ratio X)
Total #
Difference
(d)
d²
d² / e
Purple smooth
Purple wrinkled
Yellow smooth
Yellow wrinkled
Total =
Dihybrid corn – Class data (all ears of corn counted & totals combined):
Phenotypic Classes
Observed (o)
Expected Result
(e)
Total # =
(Expected ratio X)
Total #
Difference
(d)
d²
d² / e
Purple smooth
Purple wrinkled
Yellow smooth
Yellow wrinkled
31
Total =
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Karyotyping With a Plain
English Map of Human Chromosomes:
Student Guide
GLOSSARY:
Allele - one of two forms of a gene that exist at a specific gene site. One of these forms can be
dominant, such as green eyes (G) and the other form can be recessive, such as blue eyes (g).
Chromosome - a cellular structure composed of a DNA coiled around proteins. Chromosomes contain
inherited information.
Diploid cells - cells with two chromosomes from each homologous pair in humans, body cells are
diploid.
Gametes - sex cells (eggs or sperm).
Gene - a unit of heredity. Many genes consist of a sequence of DNA nucleotides that determine the
amino acid sequence of a protein.
Haploid cells - cells with one chromosome from each homologous pair. In humans, gametes are
haploid.
Heterozygous - instance where two genes that control a specific trait are different - for
example, a human with a gene for green eyes (G) and a gene for blue eyes (g).
Homologous - two chromosomes that share the same alleles.
Homozygous - instance where both genes for a specific trait are the same - for example, a human
with two genes for green eyes (GG).
Human Genome Project - a multi-national, 15-year, $3 billion project to detect the specific locations
of the genes that control human traits. There are between 50,000 and 100,000 genes in a haploid human
genome (23 chromosomes). The goal of the Human Genome Project is to identify and map all the human
genes and eventually sequence the nucleotides in their DNA.
Locus - a specific location on a chromosome where a gene can be found. Loci is the plural of locus.
Mendel's Law of Unit Characteristics - law which states that all traits are controlled by two
genes, one from the egg and one from the sperm.
Mendel's Law of Dominance - law which states that some genes are dominant over other genes
(known as recessive genes), thereby preventing the expression of the recessive genes.
Mendel's Law of Segregation - law which states that during meiosis only one gene from each gene
pair is passed on to future offspring through the sperm of egg.
Mendel's Law of Independent Assortment - law which states that during meiosis all gene pairs
are assorted independently, resulting in a variety of gene combinations, and subsequently, genetic
traits.
Multiple alleles - several forms of a gene. The ABO blood group is an example where humans can
possess one of three allele forms.
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GENERAL BIOLOGY I
IRSC Biological Sciences Department
Non-disjunction - failure of a chromosome pair to separate during meiosis, resulting in extra or
missing chromosomes.
Trisomy - a genetic condition caused by non-disjunction of chromosomes during meiosis. The result is
three homologous chromosomes with the same alleles instead of the normal pair.
BACKGROUND INFORMATION:
For the last 25 years karyotyping has been used to detect chromosome abnormalities in humans. The
chromosomes are usually obtained from blood samples. Since the white blood cells contain large nuclei,
these cells usually contain the best source of human chromosomes. Through a series of staining
procedures, the cells with the largest visible chromosomes are isolated, photographically enlarged, and
then cut out and arranged into chromosome pairs. Highly trained scientists and doctors analyze the
results to determine if there are any variations in the shape, length, or number of chromosomes. Over
the years, this technique has been used to detect, and in some cases correct or treat, an increasing
number of genetic diseases.
A related technique called amniocentesis now permits the detection of abnormal chromosome numbers in
a fetus as early as the sixteenth week of pregnancy. In this procedure, the tip of a syringe is inserted
through the mother's abdominal wall and uterus into the fluid-filled amniotic sac surrounding the fetus.
Dead skin cells and cells from the respiratory passage that enter the amniotic fluid are sucked into the
syringe. These cells can then be karyotyped and analyzed for chromosomal abnormalities.
Specific groups of chromosomal abnormalities are accounted for by the occurrence of non-disjunction.
Nondisjunction is the failure of chromosomes to appropriately separate during meiosis at Anaphase I or
Anaphase II. Non-disjunction during the first meiotic division results in the abnormality of all gametes
formed. Half will contain the paternal and maternal chromosomal haploids, giving rise to trisomic zygotes;
and half will contain no chromosomes at all, producing monosomic zygotes. Non-disjunction in the
second meiotic division can produce half of the gametes normally. In the other half, however there will
be some gametes lacking chromosomes, again creating monsomic zygotes, as well as gametes which
contain two copies of a chromosome, either paternal or maternal, producing trisomic zygotes. The
consequences of non-disjunction are serious, resulting in Down's Syndrome (three #21 chromosomes),
Turner's Syndrome (X_), and Klinefelter's Syndrome (XXY), among others.
Karyotyping can also be useful in evaluating the personal traits of babies. Characteristics such as blood
type, hair color and eye color can be determined by the presence of a gene on a specific chromosome.
Many times the paternal gene can contribute a different quality trait than the maternal gene. For
example, the paternal gene may indicate brown eyes while the maternal gene indicates blue eyes. One of
these gene traits must take precedence over the other and be expressed in the baby. The gene trait
which takes precedence is called the dominant trait; the other is recessive. The dominant gene is denoted
by a capital letter, and the recessive gene is denoted by a lower case letter. Although a baby may
outwardly display the dominant trait, it can still genotypically contain the recessive gene as well.
However, for the recessive gene to be expressed, it is necessary to have both parents give recessive
genes.
Refer to your Map of the Human Chromosomes. A key to the symbols included on this map is listed on
the following page. (These same symbols will apply to the chromosomes you will receive as part of this
lab, in which you and your partner will join to produce a "baby.") On your map, you will note that the
gene for brown eyes (B) is not listed. While it is known that brown eyes are dominant over blue and
33
GENERAL BIOLOGY I
IRSC Biological Sciences Department
green eyes, the locus of the gene for brown eyes has not been found. Due to this fact, in the following
lab, when an indication of eye color is absent in the chromosomes, it can be assumed that the dominant
brown eye gene is present. Additionally, if the indication of eye color is absent in one parent, but present
in the other, the dominant trait of brown eyes will take precedence. The gene for brown hair (B) is also
dominant over the gene for red (R) hair. Red or blond hair is only expressed when brown hair is not
coded on Chromosome #19.
As for many of the other traits noted on your map, keep in mind that all people have genes for all traits.
However, for the sake of simplicity, only the abnormal genes are shown. In fact, each chromosome
contains between 900 and 4,000 genes. This map shows only a few of the genes on each chromosome.
In this lab, you and your partner will join chromosomes, to produce a "baby." For each baby "produced"
during the lab you will need to determine eye color, hair color, and blood type. Each baby will also have
and carry a genetically-linked disease, which you will need to determine. Keep in mind that this is done
for study purposes only. In reality, very few people actually have a genetic disease. This is because even
though most people carry at least one recessive gene that, if expressed, would cause a serious genetic
disease, the recessive gene is masked by a normal dominant gene. Also, remember that genes contain
information for "putting together a person," It is only when a gene malfunctions that you get a genetic
disease.
A Sample Karyotype:
Karyotyping a baby (boy): Pink chromosomes (on right side) come from mom;
Blue chromosomes (on left side) come from dad.
34
GENERAL BIOLOGY I
IRSC Biological Sciences Department
KEY TO GENE SYMBOLS:
9 A Blood Type*
IA
11 Albinism
a
9 B Blood Type*
IB
4 Blond Hair (check #19)
r or b
7 Blue Eyes (check #19)
g or b
? Brown Eyes**
B (dominant over blue or green)
19 Brown Hair
B (dominant over R, r & b)
X Color Blindness
Xc
7 Cystic Fibrosis
c
X Duchenne Muscular Dystrophy Xd
4 Dwarfism
D
19 Green Eyes
G
X Hemophilia
4 Huntington's Disease
15 Marfan Syndrome
9 O Blood Type*
12 Phenylketonuria (PKU)
1 Rh type (negative)
1 Rh type (Positive)
4 Red Hair (check #19)
13 Retinoblastoma***
11 Sickle Cell Anemia
15 Tay-Sach's Disease
Xh
H
M
Io (recessive to I & I )
p
rh- (recessive to Rh+)
Rh+ (Dominant over rh-)
R
R
s
t
A
* Blood type of which A, B, and O are three different alleles; thus the notations I A, IB, and Io.
** The gene for brown eyes has not yet been located. Brown is dominant over blue or green.
*** Chromosome 13
NOTES:
1.) Capital letters for diseases mean that the disease will be expressed with only one allele. They
are dominant diseases.
2.) The number in front of the trait represents the number of the homologous pair (chromosomes) where found.
__________________________________________________________________________________
35
B
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Karyotyping “Babies” Worksheet
Couple
Sex
Number
Genetic Disease
Carrier
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
36
Blood
Type
Hair
Color
Eye
Color
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Karyotyping Lab:
Student Worksheet
Procedures:
Part 1: In-class Lab
To better understand "What makes you unique?” you will assume the role of mother or father and
contribute one set of chromosomes to your "offspring." Your partner will contribute a second set of
chromosomes to your "offspring." In this way, you will simulate the events that contributed to the
formation of the unique individual that is you!
1.
The envelope that you received contains paternal (male) or maternal (female) chromosomes. If
your chromosomes are pink, you are the mother. If your chromosomes are blue, you are the
father.
2.
To begin karyotyping, spread out the contents of your envelope. Your partner should do the
same with the contents of his/her envelope. Mix the contents of the two envelopes together.
Now, match up the sets of chromosomes by size, banding, etc., until all the chromosomes have
been paired off. (NOTE: Occasionally, there may be a missing or an extra chromosome; in this
instance, you will have a chromosome that will not join with another to create a matching set.)
Next, place the chromosomes that are marked with an X or a Y together. (Again, note that in
some instances there may be an extra X or Y chromosome, or one of these chromosomes may
be missing.) Then arrange the remaining sets of chromosomes in order by size and banding.
Using your Map of the Human Chromosomes as a reference, number each set of chromosomes
in order, with the longest chromatids being #1. (Do not include the X and Y chromosomes in
your numbered sets.)
3.
Fill in “Karyotyping Worksheet” chart.
4.
Answer questions 1-9 below.
Results:
Part I: In-class Lab
Answer the following questions. If necessary, attach additional sheets of paper or continue writing
on the back side of these worksheets.
1a. Normally, how many chromosomes are found in a human sperm?
1b. Normally, how many chromosomes are found in a human egg?
1c. Normally, how many chromosomes are found in a human baby?
1d. How many chromosomes are found in the "baby" you created in this lab?
2a. What form of cell division creates sperm?
2b. What form of cell division creates the egg?
37
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Karyotyping Lab:
Student Worksheet
3a. Note the two chromosomes that are not numbered. (Refer to your map for chromosome
numbers.) If these chromosomes are __________ and __________, your baby is a boy. If
they are __________ and __________,your baby is a girl. What is the sex of your baby?
3b. Is the sex of the baby readily obvious? __________ Occasionally, complications exist which
make it difficult to determine the sex of the baby. What do you think these complications
might be, and how could they occur? Explain your answer.
4. Note the arrangement of your baby's chromosomes. Study them carefully and compare them
to the chromosomes represented on the Human Chromosome map. What criterion is used to
arrange the chromosomes 1 through 22?
5. Note the genes that are found on your baby's chromosomes. Letters are assigned to
represent each genetic trait. If your baby has a combination of dominant gene, shown by a
capital letter, and a recessive gene, shown by a lower case letter, the dominant gene
prevents expression of the recessive trait. Based on this information, try to determine all of
your baby's genetic traits. List them below. (These should include any genetic diseases your
baby has, any genetic diseases your baby is a carrier of, your baby's blood type, your baby's
hair color, and your baby's eye color.)
6. What genetic disease or diseases is/are carried by the sperm?
7. What genetic disease or diseases is/are carried by the egg?
8. Based on the "Law of Dominance (see question 6), what genetic disease has your baby inherited,
if any?
9. Based on today's laboratory, write a paragraph explaining why you are genetically unique.
38
GENERAL BIOLOGY I
IRSC Biological Sciences Department
Karyotyping Lab:
Student Worksheet
Part II: Research/Report
After you complete the karyotyping lab you will discover that your "baby" has inherited a combination
of genes that result in a genetic disease. Your assignment is to find information on your baby's genetic
disease, and then write a report summarizing your findings. (Be sure to address the questions listed in
Part II below and to list your sources of information.)
Results:
Part II: Research/Report
After you complete the karyotyping lab you will discover that your baby has inherited a combination of
genes that result in a genetic disease. You assignment is to find information on your baby's genetic
disease and then write a report summarizing your findings. Be sure to address all of the following items
in your report, and to cite your sources, and include a bibliography.
1.
What is the name of your baby's genetic disease?
2.
What are the symptoms of the disease?
3.
When is the disease usually detected (i.e. at birth or later in life)?
4.
What is the frequency of carriers of this disease in the population?
5.
What is the frequency of the disease in the population?
6.
What is the mode of inheritance for this disease?
7.
Is the disease autosomal (on the first 22 pairs of chromosomes) or is it on the sex chromosome
(or X-linked)?
8.
What chromosome has been determined to carry this gene (consult your "Human Chromosome
Map")?
9.
What treatment, if any, is used for this disease? How does the treatment affect the disease?
10.
What is the prognosis, or outlook, for your baby's recovery?
11.
What future techniques might be used to correct or eliminate your baby's disease?
12.
Discuss, in detail, what difficulties, if any, a parent would encounter in raising a child with this
disease?
39
GENERAL BIOLOGY I
IRSC Biological Sciences Department
NATURAL SELECTION IN THE WILD
CO-EVOLUTION OF PREDATOR AND PREY POPULATIONS
Adapted from:
Fry, 1984, Exploring Biology in the Laboratory,
2nd ed., Saunders College Publ., Philadelphia.
Charles Darwin pointed out that some individuals produce more offspring than others,
and that this difference is related to how well individuals are adapted to their
environment. The best adapted individuals leave the most offspring – their genetic
features are transferred to the next generation more frequently than are the features of
less well adapted parents. The process is known as natural selection, and it causes
changes in allele frequency from one generation to the next. A change in allele
frequency in the population is evolution, and natural selection is the mechanism by
which evolution takes place.
In this laboratory exercise you will simulate the effects of natural selection on two
populations – a predator and its prey. At the beginning of the simulation each
population will have a variety of phenotypes. As you simulate natural selection over
three generations in the lives of these populations, you will see how natural selection
results in the survival and reproduction of particular phenotypes of predators and prey
(differential reproduction), and you will see the allele frequencies in the populations
change over time (the populations evolve). You will be able to make inferences about
physical characteristics of individuals in these populations which helped them survive
and reproduce. These physical characteristics are known as adaptations.
PREDATOR AND PREY COEVOLUTION:
1. Initial feeding bout: four predator phenotypes (forceps), 2 predators per phenotypes;
four prey phenotypes (beans) (differing in color and size: white-lg, brown-med (+),
black- med (-), & tan-small), 100 of each.
2. experiment will be carried out in the lab. on two rectangular pieces of artificial turf,
measuring approximately 1mx4m.
3. feeding bouts set at 1 min. (modify if needed in increments of 30 sec to insure
adequate prey survival. Feeding times must remain constant for all three feeding
events.)
4. split predators (8) and prey (100 seeds per phenotype) evenly between the two
feeding areas. You should end up with 1 predator from each phenotype and 50 seeds
for each prey phenotype in the first feeding bout per turf mat.
40
GENERAL BIOLOGY I
IRSC Biological Sciences Department
5. the four most successful predators will survive and one of their phenotype for each
(offspring) added to replace the four predators that will be removed (die).
6. after experiment recover seeds, sort, and return them to their respective bags (reuse
seeds, don’t throw them out).
After each feeding bout the predators will count the number of beans eaten of each
phenotype and your instructor will record these on the board. Record these data on
your own data sheet. The four most successful predators will survive and reproduce
one offspring and the other four will die and leave the game. Four new student
predators will be chosen for generation two.
The calculation of survival and reproduction in the prey population is described here and
on the data sheets. First calculate the number of each phenotype eaten by adding the
number eaten by each predator. Next calculate the number of each phenotype which
survived by subtracting the number eaten from the initial number of each phenotype
(e.g., 100 for round 1). In order to keep the number of prey available in each round at
about 400, we will have each prey phenotype reproduce in proportion to its survival (that
eaten least survives best and reproduces best). Calculate the proportion of surviving
prey which belongs to each phenotype: (proportion surviving) = (number surviving /
(total survivors). Next calculate the number of progeny of each phenotype: number of
progeny = (proportion surviving) x (total eaten). Finally, count out the number of
progeny beans of each phenotype and give them to your instructor so they can be
added randomly to the surviving prey in the predation arena. The number of prey at the
beginning of Generation 2 is equal to the number of survivors plus progeny of each
phenotype. Record these numbers on DATA FORM 2 and begin the second generation
of predation.
Repeat the calculations following Generation 2 and Generation 3. You have now
simulated the survival and reproduction of three generations of a predator population
and its prey population. Calculate the final allele frequencies of the predator and prey
phenotypes: (number of individuals with a particular phenotype) / (total number of
individuals). To complete this exercise, answer the questions in the LABORATORY
REPORT section and graph the initial and final allele frequencies for each predator and
prey phenotype.
41
GENERAL BIOLOGY I
IRSC Biological Sciences Department
DATA FORM 1
GENERATION #1
SIZE OF PREY POPULATION BEFORE PREDATION
Black
Brown
Tan
White
Total
NUMBER OF PREY EATEN
PREDATOR
TYPE
Black
Brown
Tan
White
Total
Rank
1
2
3
4
5
6
7
8
9
10
11
12
No. Eaten
Total
No. Surviving
Total
Proportion
Surviving
No. Progeny
No. Surviving = (Population Size before Predation) – (No. Captured)
Proportion surviving = (No. Surviving) / (Total Survivors)
No. Progeny = (Proportion Surviving) x (Total Captured)
42
GENERAL BIOLOGY I
IRSC Biological Sciences Department
DATA FORM 2
GENERATION #2
SIZE OF PREY POPULATION BEFORE PREDATION
Black
Brown
Tan
White
Total
NUMBER OF PREY EATEN
PREDATOR
TYPE
Black
Brown
Tan
White
Total
Rank
1
2
3
4
5
6
7
8
9
10
11
12
No. Eaten
Total
No. Surviving
Total
Proportion
Surviving
No. Progeny
No. Surviving = (Population Size before Predation) – (No. Captured)
Proportion surviving = (No. Surviving) / (Total Survivors)
No. Progeny = (Proportion Surviving) x (Total Captured)
43
GENERAL BIOLOGY I
IRSC Biological Sciences Department
DATA FORM 3
GENERATION #3
SIZE OF PREY POPULATION BEFORE PREDATION
Black
Brown
Tan
White
Total
NUMBER OF PREY EATEN
PREDATOR
TYPE
Black
Brown
Tan
White
Total
Rank
1
2
3
4
5
6
7
8
9
10
11
12
No. Eaten
Total
No. Surviving
Total
Proportion
Surviving
No. Progeny
No. Surviving = (Population Size before Predation) – (No. Captured)
Proportion surviving = (No. Surviving) / (Total Survivors)
No. Progeny = (Proportion Surviving) x (Total Captured)
44
GENERAL BIOLOGY I
IRSC Biological Sciences Department
LABORATORY REPORT:
Which prey phenotype appeared to be best adapted to local conditions of
vegetation cover and predation pressure?
Why?
Which prey phenotype appeared to be least adapted to local conditions of
vegetation cover and predation pressure?
Why?
Which predator phenotype was apparently best adapted for feeding on prey or
this particular size? ________________________________________________
________________________________________________________________
Did any predator genotype become extinct, i.e., were one or more of the alleles
controlling the size of prey capturing structures lost from the gene pool?
________________________________________________________________
If not, can you predict which predator genotype is most likely to become extinct?
Why?
Describe, in terms of adaptation and natural selection, how evolution may occur
in a natural population.
45
GENERAL BIOLOGY I
IRSC Biological Sciences Department
1.
Use the following diagram to construct histograms (bar charts) to compare the
original genotype frequencies of the predator and prey species to those
frequencies at the end of the demonstration.
Predator Allele Frequency (in percentages):
Initial
Final
100
100
75
75
50
50
25
25
0
0
Tiny Small Medium Large
Tiny Small Medium Large
PHENOTYPE
PHENOTYPE
Prey Allele Frequency (in percentages):
Initial
Final
100
100
75
75
50
50
25
25
0
0
Tan Black Brown White
Tan Black Brown White
PHENOTYPE
PHENOTYPE
46