Diffusion and Osmosis Lab Worksheet

Diffusion and Osmosis Worksheet Diffusion is the movement of particles from areas of higher concentration to areas of lower concentration. It is a natural, random process. This means that it does not require extra energy input. 1. These are pictures of molecules frozen at two different times. Draw arrows to show the direction each particle might travel due to diffusion in diagrams A and B. A. B. B 2. Diagram A shows the same number of particles as in Diagram B except most particles start out on one side of the box. Explain why after a while, Diagram A resembles Diagram B. Molecules move randomly and reach equilibrium 3. 4. 5. Give an everyday example of diffusion in air and in water.  AIR: Scents and Smells  WATER: Colored dye in a glass of water WORD BANK: Passive / Active / Lower / Higher / Unevenly / Evenly Complete the following sentence: Diffusion is the movement of particles from high concentration to a low concentration until they are evenly spread out. Moths emit chemicals called pheromones to attract a mate. a) Which process is responsible for the distribution of these chemicals through the air? Diffusion b) If a moth detects pheromones, how might it work out which direction they are coming from? Detect the higher concentration of pheromones c) What would be the advantage of a moth releasing the pheromones on a night when there was little wind? The pheromones aren’t blown away from a potential mate 6. Osmosis is the diffusion of water across a semi permeable membrane. The semi permeable membrane acts like a filter that lets only the water through. Water always goes from the area of higher water concentration to the area of lower water concentration. Confused? Then imagine the particles (or solute) are salt and follow the rule - SALT SUCKS! On the diagram to the right label the: • Semi permeable membrane (M) • Area of higher water concentration (HC) • Area of lower water concentration (LC) • Direction of osmotic flow (arrow) M LC HC WORD BANK: Salt / Water / Lower / Higher / Semi-permeable Membrane / Cell Wall 7. Complete the following sentence: Osmosis is the passage of Water molecules from a Low concentrated solution to a High concentrated solution through a Semi permeable membrane. 8. The roots of a plant have root hair cells that absorb water from the soil. The diagram below shows two different kinds of roots. The concentration of the solution inside the cell is higher than the concentration of the solution in the soil. a) Explain why water moves from the soil into the root hair cell. Water equilabrates through the semi permeable membrane moving from a high concentration of H20 outside to a low concentration of H2O inside the cell b) Suggest why root hair cells are long and thin and not short and stubby? More membrane surface area so more water can be taken up by the plant. 8. Label the following diagrams of Red Blood Cells and Plant Cells as being examples of cells contained in Isotonic, Hypertonic and Hypotonic solutions. HYPO 9. ISO HYPER Strawberry jelly is a very strong solution of sugar. By contrast the cytoplasm in bacteria is a much weaker solution. The cell wall of bacteria is made up of a semi-permeable membrane. Would water flow from the microbe to the jam, or from the jam to the microbe by osmosis? Microbe to Jam 10. How are the molecules moving in the examples below? Write OSMOSIS or DIFFUSION. a. The student sitting next to you just came from gym class and forgot to shower and you can tell. Diffusion b. After sitting in the bathtub for hours, your fingers start to look like prunes. Osmosis c. The girl sitting two rows ahead of you put on too much perfume this morning. Diffusion d. One way to get rid of slugs in your garden is to sprinkle salt on them, so they shrivel up. Osmosis e. Yum! Something smells good. The neighbors are cooking on the grill! Diffusion f. Gargling with salt water when you have a sore throat causes your swollen throat cells to shrink and feel better. Osmosis g. Oxygen molecules move from the air sacs in the lungs across the cell membranes into the blood Diffusion 11. Complete the table by writing whether solutes and water move INSIDE or OUTSIDE the cell. • Hints: With diffusion, solutes move from an area of high concentration to an area of low concentration. With Osmosis, wherever more salt is, water follows! Or, water also goes from an area of high amount of water to an area of low amount of water. DIFFUSION Does the SOLUTE move INSIDE or OUTSIDE the cell? Inside Both In Out Both Out OSMOSIS Does WATER move INSIDE or OUTSIDE the cell? Outside Both Out In Both In intracellular fluid extracellular fluid (inside the cell) (outside of cell) 5% salt 10% salt 10% salt 10% salt 3% glucose 1% glucose 2% protein 1% protein 9% salt 9% salt 13% water 25% water