Under what conditions do cells gain or lose water? Red Blood

[Pages:2]Under what conditions do cells gain or lose water?

Molecules Name

Hypotonic Solution Isotonic Solution Hypertonic Solution

Red Blood Cell: Net Water Movement In/Out In

Red Blood Cell: Appearance of Cell

Swell

Elodea: Net water Movement In/Out

In

Elodea: Appearance of Cell

Swell

In/Out

No Change In/Out

No Change

Out

Shrink

Out

Shrink

Paramecium: Net Water Movement In/Out

Paramecium: Appearance of Cell

In

Swell

In/Out

No Change

Out

Shrink

Question 1: Did water move into the cell or out of the cell while it was surrounded by hypotonic solution? -- The water moved into the cell while it was surrounded by hypotonic solution.

Question 2: In which direction did the water move through the cell membrane when the cell was surrounded by the hypertonic solution? -- The water moved out of the cell membrane when the cell was surrounded by the hypertonic solution.

Question 3: Compare and contrast what happens to an animal, a plant, and a Paramecium cell in a hypotonic, an isotonic, and a hypertonic solution. -- The hypotonic solution means the solution with the least amount of solute compared to inside the cell. -- The hypertonic solution means the solution with the greatest amount of solute compared to inside the cell. -- The isotonic solution means the solution of the concentration of solute equal the concentration inside the cell. -- when put an animal, a plant, and a Paramecium cell in a hypotonic solution, the water will move into the cell, and the cell will swell perhaps burst; when put the cells in hypertonic solution, the water will move out of the cell, and the cell will shrink; when put the cells in isotonic solution, the water will move in and out in same rate, the cell will not change. -- No matter what kinds of cells, they all work in same way.

Question 4: Could Elodea or Paramecium from a freshwater lake be expected to survive if transplanted into the ocean? Explain. -- the Elodea or Paramecium from a freshwater lake will not survive if transplanted into the ocean. Because the environment will become the hypertonic solution to the cell, and the water will move out of the cell, the cell will shrink.

Question 5: If you were to grill a steak, would it be better to put salt on it before or after you cooked it Explain why, in terms of osmosis. -- It would be better to put salt on it after cooked it.

-- Because if put the salt on it right before cook it, after the salt mix with water, the environment outside of the meat cell would become hypertonic sulution to the cell. The water in the meat cell would move out of the cell through the membrance, and the meat would be dry and tough. But if put the salt on it after cook it, the meat would be juicy.

Question 6: Why does salad become soggy and wilted when the dressing has been on it for a while? Explain why, in terms of osmosis. -- Because there are water and salt in the dressing, when they mix with vegetables, the environment will become the hypertonic solution to the plant cell. The water in the plant cell will move throgh the membrane to outside, and the plant cell will shrink. So the salad become soggy and wilted.

Question 7: An effective way to kill weeds is to pour salt water on the ground around the plants. Explain why the weeds die, using the principles discovered in this Virtual Lab. -- The salt water is the hypertonic solution to the weeds. According to this Virtual Lab,when the plant cell put into the hypertonic solution, the water in the cell will move out of the membrane, so the plant cell will shrink. This is the reason the weeds die after pour salt water on the ground around the plants.

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