Western Mindanao State University
College of Science and Mathematics
Group No.: 02
Date Performed: April 21, 2014
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
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.
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
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 observed within the cellophane bag from white to blue black solution.
C. Osmosis in Cells
About ¼ of the broad end part of the egg was broke out, and the whole egg was then immersed into a beaker containing water in upright position with the membrane exposed by supporting the egg by a pebbles. The egg immersed into the water was observed for an hour on observing its changes. D. Effect of the Different Salt Concentration of Plant Cells
A Rheo discolor mounted in to a glass slide was first examined under LPO with water as its solvent and the distribution of the pigments was noted. Without removing the slide from the stage a 10% salt solution was dropped twice into the edge of the cover. The three neighboring cells as they was appeared under LPO was drawed one minute after the addition of the 10% salt solution.
A new Rheo discolor slide was again prepared and examined under LPO but the solution added was 50% salt solution and the three neighboring cells was then again drawed. These procedure was again repeated but the slide used was a Hydrilla leaf and was examined under HPO.
IV. RESULTS AND OBSERVATIONS
A. Diffusion of Solid in Water
5.a At the end of 10 minutes, describe what took place in the beaker. 1-2 Minutes
Some of the solid KMnO4 dissolved while most of it did not and was settled in the bottom of the beaker. 2-4 Minutes
A very light pink cover was found at the upper portion of the solvent. At the bottom of the beaker were found to contain the undissolved KMnO4.
The cover of the solvent changes from light pink to pink. There were still undissolved KMnO4 found in the beaker. 6-8 Minutes
Some of the undissolved KMnO4 at the bottom of the beaker rose which turns the color of the solution to a light pink. 8-10 Minutes
More solid KMnO4 rose from the bottom of the beaker which turns the color of the solution the dark pink. There was still undissolved KMnO4 in the beaker. 5.b Suggest...
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