Osmosis happens when water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane is equal. (Reese, 2011). Active Transport is the type of transport of molecules where energy is supplied to the transporter system to transport in the direction opposite to a concentration gradient. (Hickman, 2008). The objectives of our experiments are to characterize the plasma membrane and to differentiate diffusion, osmosis and active rainspout.
II. Methodology A. Structure of the Plasma Membrane i. We mixed 5 ml of water and cooking oil into a test tube by shaking it. Then we observed the mixture as it settles for five minutes. We shook the test tube again and took a sample into a slide before it settled. We observed it under the LOOP of the compound microscope. Ii. We placed cooking oil into a Petri dish, and dropped an egg solution into it. We observed it for a formation of a membrane, then puncturing it. Iii. We placed the evaporated milk in a beaker until it is % full and heat it.
We then observe the formation of milk skin at the top. Second is to remove the milk skin and heat again. Observe what happens. B. Selective action of the Plasma Membrane i. We prepared three test tubes, L abele accordingly, with Mil of aqueous yeast suspension and three drops of Congo red solution. We added 4 drops of 40% formalin into the first test tube, heated the second one, and let the third stand as it is. We each took a drop of each in a slide and observed it. Ii. We placed 10 ml of alkaline yeast suspension in a 100 ml beaker then added 10 ml of Neutral red Solution.
After observing it, we filtered 5 ml of the mixture through a filter paper o separate the yeast from the liquid. C. Permeability i. Diffusion a. We placed a pinch of Potassium Permanganate (Km) and Methyl-blue crystals on top of an agar that was in a Petri Dish. B. We filled up a test tube with a collision solution and slowly rotate it until a thin film covers the entire inner surface of the test tube. We placed the test tube in a rack in an inverted position to let it dry. After ten minutes, we removed the collision gently and slowly with the use of water. We poured in a part of 50% glucose and 2 parts of starch solution.
We tied the end of the collision and rinsed its outside. We let it soak in a ml beaker containing ml water and ml 2% iodine. After two minutes, we took samples of the solution and tested it with iodine potassium iodide, for testing the presence of starch, and Benedicts solution, for the presence of Glucose. Ii. Hemolytic and Creation of Red Blood cells. We prepared three slides with 1-3 labels. Then, we paced a drop of 0. 9% Nasal on the first, 10% Nasal to the second and a drop of distilled water on the third. Then we had a volunteer to put a drop of his blood to each of the slides.
Then we covered the slides with a cover slip and viewed it under the microscope. Ill. Results and Discussion i. When we mixed the oil and water, it assumed a yellowish-whitish color which gradually separates from each other. And when we viewed the mixture under the microscope, the image that it showed was bubbles, water molecules, which are not really mixed in the oil. Ii. The egg solution Looked like a bubble in the oil. Then when we ruptured its membrane, the egg solution spreads in the oil. And it formed another membrane- like envelope. Iii. After we removed the first skin that formed, another skin formed.
The skin is formed due to the chemical reaction hat affects the structure of proteins and fat molecules. When water evaporates from milk during heating, the milk’s protein and fat molecules become more condensed on the surface. B. Selective action of the Plasma Membrane i. The results of this experiment are in a table below. Test Tube # Content/Procedures Observations Alkaline yeast suspension, Congo Red solution and formalin. The mixture had a dark reddish-violet color. 2 Alkaline yeast suspension and Congo Red solution heated on an alcohol lamp. As we were heating it, the mixture darkened slightly, a few shades darker than the third. Alkaline yeast suspension and Congo Red solution left as it was. This was left as it is and has a bright red solution. Ii. When we mixed the alkaline yeast suspension with the red solution, the Neutral red solution assumed a dark red color. When we filtered the yeast, the cells in the filter paper have a deep red color and the residual solution has a yellowish-orange color. The color of an acidic solution is Red, while a basic solution is yellow-orange. The cells affected the extracurricular fluid, such that the basic Ph level of the suspension was affected.
Since the yeast cells are very acidic, even in basic solutions, it goes through diffusion until the whole solution is in equilibrium. When we filtered the cells, the alkaline solution went bank to its original basic nature. C. Permeability a. When we placed the Km, which originally has a blackish-brown color, it diffuses in the agar acquiring a purple color. And after some more time, it became reddish-orange color. While the Methyl blue crystals diffused at a much slower rate. It has a deep blue color. Just like in an Agar, Small molecules can pass through the cell membrane by diffusing themselves into the membrane.
The rate of diffusion is faster with compounds of low molecular weight, while it is slower with compound with a high molecular weight. B. Observations: Time Test for presence of Starch Test for presence of glucose After two minutes Negative. The mixture did not have any color change. Negative. But after heating the Solution, the mixture had a bluish-brown color. After four minutes Negative. But after heating the Solution, the mixture had a brown color. After six minutes Negative. But after heating the Solution, the mixture had a reddish-brown color.
Since all results are negative, there were no molecules that passed through the collision. But there was an observed change in color with the Benedicts test. Ii. Hemolytic and Creation of Red Blood cells The first slide gave an image of an equal coloration of yellow and red. Then the second one showed an image with a red cell with some yellow. While the last gave an image of red with a larger area of yellow. Blood cells have a 0. 9% Nasal in their intracellular fluids. The first slide is Isotonic because the extracurricular and intracellular fluids are in osmotic equilibrium.