Download DIFFUSION AND OSMOSIS PRE-LAB

DIFFUSION AND OSMOSIS PRE-LAB
Lab Bench Activity: http://www.phschool.com/science/biology_place/labbench/lab1/intro.html
Go through the Lab Bench activity answer the questions, checking your answers, and taking your time
to attempt to understand the concepts. Make notes as you go and write down your answers as you
are prompted.
Lab Walk Through Video: http://www.youtube.com/watch?v=LeS2-6zHn6M&feature=c4-overviewvl&list=PL0B4CED0AB112B993
For extra information on Water Potential (we will revisit this soon), view:
http://www.youtube.com/watch?v=jgqYlSKoXak&feature=c4-overviewvl&list=PLllVwaZQkS2pjZ33Iwr84PutjISWnYL1H
Pre-Lab Questions: Complete these questions with your group after you have individually completed
the above activities.
1. What Is kinetic energy and how does it differ from potential energy?
2. What environmental factors affect kinetic energy and diffusion?
3. Why do these factors alter diffusion rates? How do they affect rates?
4. How are gradients important in diffusion and osmosis?
5. What is the explanation for the fact that most cells are small and have cell membranes with
many convolutions (folds)?
6. What is water potential?
7. Will water move into or out of a plant cell if the cell has a higher water potential than the
surrounding environment?
8. What would happen if you applied saltwater to a plant?
9. How does a plant cell control its internal (turgor) pressure?
Water Potential Problems: Give these a shot  Use the hand out I gave you and your formula sheet.
1. Calculate the solute potential of a 0.1 M NaCl solution at 25oC. If the concentration of NaCl
inside the plant cell is 0.15 M, which way will the water diffuse if the cell is placed into the
0.1 M NaCl solutions?
2. What must the turgor pressure equal if there is no net diffusion between the solution and the
cell.