Virtual Osmosis Lab

Biology—Virtual Homeostasis “Osmosis” Lab Virtual osmosis lab Background Osmosis is a passive form of transport. Specifically, it is facilitated diffusion of water with a channel protein. Osmosis is the movement of water from a high concentration of water region to low concentration of water region. However, we do not refer to the concentration of water in a solution. Instead, we refer to the concentration of the solute in a solution. In osmosis, water moves from a low solute concentration to a high solute concentration. Purpose The purpose of this lab is to observe the effects of osmosis using dialysis tubes as a model of a cell. Hypothesis (Before you begin the simulation) Answer each question by using the highlighting tool to select your guess (“If…then…”). 1. Dialysis tubes left in distilled water with no solute added will: a) Swell b) Shrink c) Remain normal 2. Dialysis tubes left in distilled water with 5g of salt/sugar will: a) Swell b) Shrink c) Remain normal 3. Dialysis tubes left in distilled water with 10g of salt/sugar will: a) Swell b) Shrink c) Remain normal 4. Dialysis tubes left in distilled water with 15g of salt/sugar will: a) Swell b) Shrink c) Remain normal 5. Dialysis tubes left in no water will: a) Swell b) Shrink c) Remain normal Procedure: Biology—Virtual Homeostasis “Osmosis” Lab  Follow virtual lab instructions carefully. Record ALL data. Data 1. Sketch beakers. Make sure to label beakers with corresponding letter and the grams of salt solution. 2. Use measurements from Day(s) 1 and 2 to fill out data chart below. Beaker with Salt solutions Initial Mass of (cell) Final Mass of (cell) Type of Solution to cell (hypertonic, isotonic, or hypotonic) 17.66 % Chang e of Mass 82% A (control) 17.59 B (0%) 8.75 10.40 89% HYPONTONIC C (5%) 11.24 12.10 87% HYPONTONIC D (10%) 10.71 10.57 89% HYPERTONIC E (15%) 18.05 15.60 84% HYPERTONIC ISOTONIC Math help: To calculate the % change of mas masss = Final Mass−Initial Mass ×100 Initial Mass Discussion Answer the following discussion questions to help you carefully create a conclusion. Answer each question by using the highlighting tool. Biology—Virtual Homeostasis “Osmosis” Lab 1. A normal plant cell holds water in the vacuole of the cell. This large organelle also gives the cell support. Suppose a plant is submerged in salt water. As a result, the vacuoles collapse and the leaves wilt. This condition is called plasmolysis. Which explanation do you think best describes what happens to the cells of that plant during plasmolysis? A) The water diffuses out of the cell to equalize the solute concentrations. B) The water diffuses into the cell to equalize the solute concentrations. C) The solute (salt) moves inside the cell to equalize the solute concentrations. D) The solute (salt) moves inside the cell to equalize the solute concentrations . 2. The images below show the same cell, before and after reaching equilibrium. Which statement best describes what happened as the volume of the cell increased? A. The number of solute particles inside the cell decreased. B. The number of solute particles outside the cell decreased. C. The number of solvent particles inside the cell decreased. D. The number of solvent particles outside the cell decreased. 3. Which of the following bar charts describes a system in solution equilibrium? A. Graph A that is Biology—Virtual Homeostasis “Osmosis” Lab B. Graph B C. Graph C D. Graph D 4.Using the information below, what will happen to the cell as it reaches equilibrium? A. The cell will get smaller. B. The cell will get bigger. C. The cell will stay the same size. D. The change in cell size cannot be determined. 5. A sample of seaweed contains two liters of water and has 100 grams of salt dissolved in its cells. The seaweed is placed in a bucket with 4 liters of water and 300 grams of dissolved salt. What will occur when the system reaches equilibrium? A. The seaweed will absorb 40 grams of salt. Biology—Virtual Homeostasis “Osmosis” Lab B. The seaweed will lose 0.5 liters of water. C. The seaweed will absorb 1.0 liters of water. D. The seaweed will absorb 5.5 liters of water.