Osmosis and Diffusion Practice

Osmosis and Diffusion Practice Name: I. Based on what you’ve learned, in your own words, answer the following questions regarding movement of materials through a cell membrane.

1. What does semi-permeable mean?

2. What is the net movement of molecules from high to low concentrations?

3. What is the term for the diffusion of water?

4. What does dynamic equilibrium mean?

5. What is a hypertonic solution?

6. What is a hypotonic solution?

7. What is an isotonic solution?

II. Observe the diagrams in the table below. Assume that the dots are dissolved small non-polar particles on either side of the cell membrane. They are like oxygen molecules that can go across the membrane. Do the following situations represent concentration gradients? If so, in which direction would diffusion occur? Draw arrows from the appropriate molecule to represent the movement.

Gradient? Yes Gradient? Yes Gradient? No Yes or No Yes or No Yes or No? Net movement Right Net movement Left Net movement None left, right, or left, right, or left, right, or none none none III. Observe the diagrams in the table below. Assume that the dots are dissolved particles (like protein or carbohydrate molecules) on either side of the cell membrane. Do the following situations represent concentration gradients? If so, in which direction would osmosis occur? = water, = dissolved particle. Again, use arrows to show the movement of the appropriate molecules.

Gradient? Yes 1free Gradient? Yes 7:1 Gradient? No. 3:3 Yes or No water Yes or No Yes or No? molecule:5fwm Net Left (2 Net Right (3 Net None movement movement movement left, right, or water) left, right, or water) left, right, or none none none IV. Observe the table below. Are the following hypotonic, hypertonic, or isotonic solutions? Which way will water mostly move? (some situations may have water moving equally) intracellular extracellular fluid Hypotonic, Hypertonic, water moves mostly fluid (outside of the Isotonic inside or outside the cell (inside the cell) cell) 5% salt 10% salt Hypertonic outside 10% salt 10% salt Isotonic 3% glucose 1% glucose Hypotonic inside 2% protein 1% protein Hypotonic inside 9% salt 9% salt Isotonic 13% water 25% water Hypotonic inside 59% water 45% water Hypertonic outside 90% water 92% water Hypotonic inside 74% glucose 87% glucose Hypotonic inside 50% Salt Solution Hypertonic V. Observe the diagram and answer the questions. The boxes represent different solutions the same cell is placed in.

1. Label the boxes hypertonic, hypotonic, or isotonic.

2. What will happen to the cell if it is placed in a 50% salt solution? (draw 1 0 % arrows showing water’s net movement) s a l t Cell will shrink as water moves out to equalize the free water molecule concentration on both sides of the membrane. 3. What will happen if the cell is placed in pure water? (draw arrows showing water’s net movement) Cell will swell as water moves out to equalize the free water molecule concentration on both sides of the membrane. Pure Water Hypotonic