Diffusion Osmosis Lab Questions

Hall/McDougalName______

Date ______

Period

Diffusion Osmosis Lab Questions

Potato Questions

1. Describe the results of the experiment—explain trends in the data using the graph.

1. Why did the potato gain mass? Use the words hypotonic and osmosis in your answer.

1. Why did the potato lost mass? Use the words hypertonic and osmosis in your answer.

1. What would the concentration of the solution have to be for the potato to have no change in mass? Explain why, using the words isotonic and osmosis in your answer.

Starch Questions

1. Based on your observations, compare the size of each of the following molecules (sucrose molecules, water molecules, iodine molecules, starch molecules) to the size of the pores in the saran wrap (cell membrane).
2. The size of iodine molecules are ______the membrane pore size.
3. The size of starch molecules are ______the membrane pore size.

1. What results would you expect if the experiment was set up incorrectly: the water and iodine solution was placed inside the test tube, and the starch solution was placed in the beaker.

You and your group will draw a summary question from a hat. Debate the answer in your small groups (of 4 students), and come up with an answer. Check your answer with the teacher, and when you have been OK’d, you will write you answer, legibly, on a piece of butcher paper. These questions will reappear on your next assessment, so you are accountable for your classmates’ learning!

1. In the winter, icy roads are often salted to remove the ice and make them less slippery. Grasses and other herbaceous plants, often die near the side of these roads. What causes this to happen?

1. When a person is given fluid intravenously (an IV) in the hospital, the fluid is typically a saline solution isotonic to human body tissues. Explain why this is necessary.

1. What if the unthinkable happened at the hospital! A patient was given an IV bag with distilled water in it rather than saline solution. Describe what would happen to their red blood cells and explain why this would occur.

1. Many freshwater one-celled organisms, like Paramecium, have contractile vacuoles. These structures collect and pump out excel water that accumulates in the cell. Explain why these organisms need such a structure.

1. Many freshwater one-celled organisms, like Paramecium, have contractile vacuoles. These structures collect and pump out excel water that accumulates in the cell. Explain why one-celled organisms that live in salt water do not need contractile vacuoles.

1. Popcorn sold at movie theaters is very salty, causing people to become thirsty and to buy soft drinks. Explain why salty popcorn causes this thirst.

1. In many animals, glucose, rather than starch, is transported by the blood through the body to all cells. In the digestive system, starches are digested by amylase to yield glucose. Based on the findings of this lab, explain why the digestion of starch to glucose is necessary.