College of Science and Mathematics
Zamboanga City
Group No.: 02 Date Performed: April 21, 2014 Group Members: Date Submitted: April 25, 2014 Reales, Pharra Anthea O. Pendergat, Ellyssa Mae A. Pedroza, Rikko Jeremy C. Dinorog, Ivy Mae V.
BIO 101 LABORATORY
Activity No.: 4
Movements of Materials Across Membrane I. INTRODUCTION Many important reactions and processes in materials occur by the motion of atoms in the solid (transport), which happens by diffusion. Inhomogeneous materials can become homogeneous by diffusion, if the temperature is high enough. When substances are brought in contact with each other they intermix, this property is known as Diffusion. This property of diffusion takes place very rapidly in case of gases and to a lesser extent in case of liquids, whereas solids do not show this process of diffusion with each other. But what we can observe in case of solids is that the diffusion of solids in liquids takes place at a very slow rate. Molecules of solute are in constant random motion due to the collision between molecules of solute and that of the solvent. II. OBJECTIVES
1. Describe how diffusion takes place.
2. Distinguish between diffusion and osmosis.
3. Demonstrate osmosis in cells.
4. Describe hypotonic, isotonic, and hypertonic solutions.
5. Explain the effect of the different salt concentrations on cells
III. PROCEDURE
A. Diffusion of Solid in Water A pinch of potassium permanganate was dropped into a 250ml beaker containing water. The beaker was left undisturbed and was observed for 10 minutes with an intervals of every 2 minutes.
B. Diffusion through Membrane A cellophane was filled with a starch solution up to a height of about 1 inch. The cellophane bag was tied tightly assuring of no air was traps inside. Then the cellophane bag with starch solution was immersed in a beaker containing Lugol's iodine solution. The set up was observed and timed until the change in color was