AP Biology Unit 2
LabBench Lab 1: Diffusion & Osmosis
Directions: Review the processes of diffusion and osmosis by completing the LabBench Activity
Diffusion and Osmosis. To explore this activity, enter the following URL in your search engine: http://
www.phschool.com/science/biology_place/labbench/lab1/intro.html. Once you have accessed the
LabBench Lab 1: Diffusion & Osmosis complete: Key Concepts, Design of the Experiments, Analysis
of Results, and Lab Quiz by reading the information presented, watching the animations, and
answering all questions in your Comp Book.
Key Concepts
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Concept 1: Diffusion (read)
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Concept 2: Osmosis (read)
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Closer Look: Osmosis (read / animation)
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Concept 3 Movement of Molecules in Solution (read / animation)
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Closer Look: Concentration Gradient (read / animation))
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Concept 4: Movement of Molecules and Cells (read / animation)
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Concept 5: Types of Solutions Based on Solute Concentration (read / answer question)
1. Will there be a net movement of water between two isotonic solution?
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Concept 6: Water Potential (read / animate / answer question)
2. Why don’t red blood cells pop in the bloodstream?
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Concept 7: Calculation Water Potential (read)
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Concept 8: Water Potential
3. Can a solution with a molarity of 0.2 by in equilibrium with a solution with a molarity of 0.4?
Design of the Experiment
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Exercise 1: Diffusion (read / animate)
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Exercise 2: Osmosis (read / animate)
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Exercise 3: Water Potential of Potato Cores (read / animate)
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Exercise 4 & 5: Water Potential & Plasmolysis (read / animate)
Analysis of Results (read / solve practice problems)
4. The molar concentration of a sugar solution in an open beaker has been determined to be 0.3M.
Calculate the solute potential at 27 degrees. Round your answer to the nearest hundredth.
5. The pressure potential of a solution open to the air is zero. Since you know the solute potential of
the solution, you can now calculate the water potential. What is the water potential for this
example?
Lab Quiz
6. Which beaker(s) contain (s) a solution that is hypertonic to the bag?
7. Which bag would you predict to show the least change in mass at the end of the experiment?
8. Arrange the beakers in order of the mass of the bags inside them after the experiment has run for
30 minutes. List the bag the loses the most mass.
9. In beaker B, what is the water potential of the distilled water in the beaker, and the beet core?
10.Which of the following statements is true for the diagrams?