Eukaryotes, Prokaryotes, and Viruses: Structure and Function
Student Name Vicki Gonzales
Date 2/28/2022
1.
Prelab Questions
1. There are three panels in the figure below (as labeled). Each panel
represents two compartments separated by a semi-permeable
membrane. Small solid circles represent water and larger hashed circles
represent a solute. In each panel label each side (“Side A” and “Side B”)
as either hypertonic, hypotonic, or isotonic. After doing this, illustrate (with
an arrow) or state which direction water will move (left-to-right,
right-to-left, or neither). Panel 1 would move from side a to b because
the solutes on side b are higher, side a is hypertonic while side b is
hypotonic. Panel 2 would not move from either direction because each
side has the same amount of solute. Both sides a and b are hypertonic
which would make them isotonic. Panel 3 would move from side b to a
because side a has more solutes than side b. Side a is hypotonic and side
b is hypotonic.
→→→→→→→→
neither
←←←←←←←←←←
2. IKI (also called iodine-potassium iodide) is a reagent that turns black in the
presence of starch. Benedict’s regent is a reagent that turns clear blue in
the presence of glucose. As a student in BIO111 you are asked to set up
an experiment that has a beaker that has been partitioned by a
semi-permeable membrane and you have placed a solution contain 20%
glucose on one side of the beaker while on the other side you have
placed a solution containing 20% starch. See figure below.
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Considering this setup answer the following questions:
a. After two hours you remove a sample from side A and B and test
them for starch and glucose using the IKI solution and benedict’s
reagent. Predict, or hypothesize, what you will find for both side A
and side B given this scenario. Why did you make that prediction?
The sample would test
b. After making your prediction you carry out the test and find that
glucose is found on both sides A and B. However, starch is found
only on side A. Why do you think this is the case? Answer this
question by discussing the molecular difference between glucose
and starch.
c. How does the scenario described in b. compare to a biological
membrane?
3. In Activity 1 of this lab we will be investigating the impact that the surface
area-to-volume ratio has on the rate of diffusion. Please read the
directions for Activity 1 in the investigative manual. After doing so fill in
your purpose and hypothesis statements found under the Activity 1
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heading. After completing the lab come back to this section and fill out
your evidence/claims and reflection statement.
Activity 1
Instructions:
1. Open the investigative manual. Locate all the needed materials
supplied in the kit and those you will need to supply yourself.
2. Lay them out in your work area.
3. Read through the entire set of instructions found in the investigative
manual for the activity to avoid making mistakes when you go to
execute the experiment.
4. Once you have read through the instructions go back to step 1 and
begin executing the experiment.
5. Please answer the questions below and/or append appropriate
representations of data (photos, graphs, etc). REMEMBER don’t clean
up until you have taken the appropriate photos of your experiment as
described below.
Purpose statement: (This should be the question the experiment is attempting to
address. It should be written as a question.)Do molecules pass more efficiently in
and out of a cell with a larger surface-to-volume ratio than a cell with a small
surface -to-volume ratio?
Hypothesis statement: (This should be an “if/then” testable prediction that
addresses the question/purpose of the lab.)If the surface-to-volume ratio is
larger than that of a smaller cell then the iodine shouldn't penetrate as far into
the potato as the potato with a smaller surface-to-volume ratio.
Evidence/Claim statement: (This should be a statement regarding whether your
hypothesis was supported or refuted and what data/evidence allows you to
make this claim.)Evidence from the experiment shows that the surface
area-to-volume does play a role in how much the iodine permeates the potato.
In the 2.50cm potato, the surface area-to-volume was .8 while the .50cm potato
had a surface area-to-volume of 12.(carolina, 2016)
Reflection statement: (This should be a statement of what you learned, how your
understanding changed, if you have new questions, and what connections can
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you make between the lab and the content in the book and other
assignments.)What i learned is the cell structure has everything to do with how
the cell allows things to pass through its membrane. that size and structure does
effect how a cell functions .
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Photo 1 – Activity 1
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Take a picture and insert the image(s) of your potato blocks after step 5 of the
“Procedure” section in activity 1 of the investigative manual:
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Data Table 1A
Length
(l) (cm)
Width (w)
(cm)
Height
(h)
(cm)
Size of cross
section slice
(h x w) (cm)
Distance traveled
by IKI
from potato edge
(cm)
Area of white
region
(l × w) (cm2)
2.50
2.50
2.50
6.25 cm
.5 cm
4 cm ^2
2.00
2.00
1.00
2 cm
.8 cm
3cm^2
1.50
1.50
1.50
2.25 cm
1.25 cm
2.56cm^2
1.00
1.00
1.00
1 cm
.9 cm
2 cm^2
2.00
0.50
0.50
.25 cm
.45 cm
1.56cn^2
0.50
0.50
0.50
.25 cm
.4 cm
1 cm^2
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Data Table 1B
Lengt
h (l)
Widt
h (w)
Heigh
t (h)
Surface
area of
block (l x
w x 2) + (w
x h*4)
(cm2)
2.50
2.50
2.50
37.5cm
^2
2.00
2.00
1.00
16cm^
2
1.50
1.50
1.50
13.5cm
^2
1.00
1.00
1.00
6cm^2
0.50
0.50
2.00
0.50
0.50
0.50
1.5cm^
2
1.5cm^
2
Volum
e (l x w
x h)
(cm3)
15.63
cm^
3
4cm
^3
3.375
cm^
3
1cm
^3
15c
m^3
.125c
m^3
Surface
area-to-volu
me ratio
(Surface
area of
block/volum
e)
.8
.5
4
6
5
12
Surfac
e area
of slice
(w x h)
(cm2)
6.25
cm^
2
2cm
^21.
2.25
^2
1cm
^2
.25c
m^2
.25c
m^2
Surface
area of
white
section
(cm2)
Surface
area of
black
section
(cm2)
Percent of
potato block
saturated with
IKI: (Surface
area of black
section/surfac
e area of
slice)*100
4cm^
2
2cm^
2
1.5cm
1.8cm
^2
.2cm
^2
1,3 cm
.75^2
1.5^2
1.5
.2cm^2
.05cm
^2
.05cm
^2
.8cm
^2
2cm^
2
2cm^
2
1.4
1.09
1.09
1. Go back to the prelab and fill in the “Evidence/Claim” and “Reflection”
statement for this lab activity.
2. Make a line graph of the “percent of potato block saturated with IKI” (y-axis)
vs. “Surface area-to-volume ratio” (x-axis) and answer the questions below.
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a. Insert graph here (make sure your graph has a title, labeled axis, and a
legend):
b. What does this graph, and the results of this experiment, tell us about
how the rate of diffusion changes with changing
surface-area-to-volume ratio? This shows that the surface
area-to-volume is larger than that of the full penetration on a smaller
object. whereas on a larger potato, the surface area is smaller but the
penetration is larger. This is because cells are able to pass through
faster on a larger object than one smaller. (carolina,2016)
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c. Finally, what can we conclude from these results regarding why
biological cells are small rather than large? The conclusion is that the
cells are smaller because a smaller potato is over taken by iodine
faster due to the cell needing more oxygen and nutrients to be able to
do its job while the larger potato is able to do the process faster
because it is able to hold more oxygen and nutrients at the same time
as functioning
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Activity 2
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1.
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1
1
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Photo 1 – Activity Take a picture and insert the image(s) of your dialysis tubes
after step 14 of the “Preparing the Dialysis Tubing” section in activity 2 of the
investigative manu
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Data Table 2
Sample data shown.
Solution
in cup
Initial
volume
(Vi) (mL)
Final
volume
(Vf) (mL)
Change
in
volume
(Vf-Vi)
(mL)
20%
sucrose
20%
sucrose
90 mL
90 mL
0mL
0%
isotonic
B
40%
sucrose
20%
sucrose
90 mL
92 mL
2 mL
2.22%
increase
hypotonic
C
20%
sucrose
40%
sucrose
90 mL
89 mL
1 mL
1.11%
decrease
hypertonic
Treatment
Solution in
dialysis
tubing
A
Percent change
2mLin volume
(Vf-Vi)/Vi (mL)
The solution
inside the tubing
was hypotonic,
isotonic or
hypertonic?
1. Explain what the change in volume of the dialysis tube indicated. Describe
what happened when the volume increased and when the volume
decreased. During the experiment, the volume of the granulated cylinder
changed or stayed because of the transfer of solutes. In the solution of (20%
sucrose, 20% sucrose) the volume stayed the same because the dialysis
tubing neither released the solution nor gained water making it isotonic. In
the (40% sucrose, 20% sucrose) the dialysis tubing gained water from the
granulated cylinder causing the volume to increase making it hypotonic.
finally, the (20% sucrose, 40% sucrose) released its solution from the dialysis
tubing into the surrounding water of the granulated cylinder causing the
water to decrease making it hypertonic.(Carolina manual, 2016)
2. Are the results of your experiment consistent with what you would have
expected to happen? Why or why not? The results of both a and b are what
was expected however sample c was thought to be heavier than both
samples a and b. I figured with the solution of 40% being on the outside it
would transfer into the dialysis tubing and be heavier in weight.
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Activity 3
Instructions:
1. Open the investigative manual. Locate all the needed materials
supplied in the kit and those you will need to supply yourself.
2. Lay them out in your work area.
3. Read through the entire set of instructions found in the investigative
manual for the activity to avoid making mistakes when you go to
execute the experiment.
4. Once you have read through the instructions go back to step 1 and
begin executing the experiment.
5. Please answer the questions below and/or append appropriate
representations of data (photos, graphs, etc). REMEMBER don’t clean
up until you have taken the appropriate photos of your experiment as
described below.
Photo 1 – Activity 3
Insert the photo or scan of your prokaryotic cell drawing from Activity 3. The
following should be indicated in this photo:
● cell membrane type
● circular DNA
● ribosomes
● flagellum (if applicable)
● Identification of the cell tracing your steps through the Dichotomous key
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o For example: 1a 🡪 2a 🡪 3a (Staphylococcus aureus)
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Photo 2 – Activity 3
Insert the photo or scan of your eukaryotic cell drawing from Activity 3. The
following should be indicated in this photo:
● double-stranded DNA inside a nuclear membrane
● ribosomes
● mitochondria
● endoplasmic reticulum
● lysosomes
●
●
●
●
●
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Golgi apparatus
vesicles
optional internal organelles
means of locomotion if applicable
Identification of the cell tracing your steps through the Dichotomous key
o For example: 1a 🡪 6a (plasmodial slime mold)
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Photo 3 – Activity 3
Insert the photo or scan of your virus drawing from Activity 3. The following
should be indicated in this photo:
● capsid shape
● DNA or RNA, if it is single stranded or double stranded, and the replication
direction
● Identification of the cell tracing your steps through the Dichotomous key
o For example: 1a 🡪 2b 🡪 9a 🡪 10b (unidentifed)
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sources: Carolina Biological Company. (2016). Cell structure and function:
eukaryotes, prokaryotes and viruses. investigation manual and lab
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