Solved by a verified expert:Cell Membrane Transport
Exercise 1 –
Diffusion through an Artificial Membrane
Data
Table 1 – Changes during Dialysis
Color
Before
Dialysis
After
Dialysis
Solution
in Dialysis tubing
Solution
in Cup 1
Data
Table 2 – Benedict’s test Results
Tube
Contents
Color Before
Heating
Color After
Heating
#1 IKI solution from cup 1
#2 Dialysis bag solution from cup 2
#3 Distilled water
Questions:
1. Which
of the tubes #1, #2, or #3 is the control for this experiment?
2. What
color change did you observe inside the dialysis tubing? What does that change indicate?
3. Was there a color change in the water surrounding
the tubing? If so, explain.
4. What
color change(in the liquid) was observed in the water containing the IKI after
heating? What does that change indicate?
5. Did
you notice any precipitate in the tubes after heating? If so, what color was it? Which tubes was it present in?
6. What
does the Benedict’s reagent detect?
7. What
does the IKI solution detect?
8. Is
the transport mechanism observed here passive or active? Why?
Exercise 2 – Diffusion at
Different Temperatures
Data Table 3 – Diffusion of KMnO4 at
Various Temperatures
Temperature
inside cup
Color
of water
0
minutes
5
minutes
#1 Cold _______________
#2 Ambient ________________
#3 Hot ________________
Questions:
1.
State a general hypothesis to cover how temperature
affects rate of diffusion.
2.
Did all of the solution in the tubes change color within
5 minutes? If so, which tubes?
3.
If you had any tubes that did not change color within 5
minutes, how much longer would you speculate it would take to change colors? Explain your answer.
4.
Do you think if the test tubes were larger and held more
water the results would be the same?
Explain your answer.
5.
How does temperature affect the rate of diffusion?
Exercise 3 – Tonicity and Diffusion
Data
Table 4-Potato Dimensions
Tubes
of Potato
Potato
Weight Before Osmosis
(grams)
Potato
Weight After Osmosis
(grams)
Weight
Change
(grams)
#1
Distilled water
#2 10%
Sodium Chloride
Using the
information from Data Table 4, fill in the following chart. Describe the
tonicity for the potato cells compared to each tube solution and describe the
tonicity of the tube solutions compared to the potato cells. Which is isotonic, hypertonic, or hypotonic
and how did the water move? (into the
cell, our of the cells, no water movement)
Tubes of Potato
Hypotonic, Hypertonic, or Isotonic
Describe the movement of water
Potato
Tube contents
#1
#2
Questions:
1.
What
is the condition of each potato strip after soaking in the test tubes for an
hour? Which one is limp and which one is
crisp?
2.
How
would you explain the difference in the conditions of the potato strips using
the concept of tonicity?
3.
How do the changes in the conditions of the potato
strips relate to the wilting of plants?
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