Read Laboratory #1 Osmosis and Diffusion to Answer the Following Pre-Lab Questions
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Read Laboratory #1 Osmosis and Diffusion to answer the following Pre-lab Questions.
The two things that we will be looking at are the processes of osmosis and diffusion and the effect of solute concentration on water potential.
1. Define the following terms: diffusion
osmosis
water potential
2. What happens at equilibrium?
3. Define dialysis. Explain what determines if a substance is able to pass through a membrane.
4. Do you expect glucose to move out of the bag (dialysis tube)? ______Why or why not?
How will you test this?
5. Do you expect starch to move out of the bag (dialysis tube)? ______Why or why not?
How will you test this?
6. Do you expect water to move out of the bag (dialysis tube)? ______Why or why not? How will you test this?
7. Do you expect Lugol’s Iodine to move into the bag? ______Why or why not?
How will you test this?
8. In Fig. 1.1 in the Lab #1 packet, identify the hypotonic solution
______; the hypertonic solution ______; and the net direction of initial water flow ______.
9. A dialysis bag contains a sucrose solution of 0.6M. The beaker into which it is placed has a concentration of 0.3M. Is the dialysis bag hyper or hypotonic to the beaker solution? ______. In which direction is the water expected to travel?
10. What concentration of sucrose solution would the beaker need to contain for there to be no net movement of water between the 0.6M bag and the beaker? ______
11. What are the two components that influence water potential?
12. If a potato core is placed in pure water, in which direction would you predict the net flow of water to travel (if any)? Why?
13. Discuss the difference between plant and animal cells when placed in hypotonic solutions.
14. How does the movement of water relate to pressure? Give an example to illustrate this.
15. Increasing pressure increases or decreases the water potential number (circle one). 16. Increasing solute concentration increases or decreases the water potential number (circle one).
17. Circle the correct phrase:
Water will go from an area of -3 water potential to 0.
Water will go from an area of 0 water potential to -3.
18. If you continue to add solute to our potato cells what will happen to them?
19. Define plasmolysis.
20. Explain what you would expect to happen if you put salt on watermelon (very yummy). What about salt on slugs in your garden (very cruel).