Bio. Lab. Report - Membrane Transport

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Objectives: To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells. Materials and Apparatus: * Microscope * Electronic balance * Stirring rod * Small knife * Glass slide and cover * 250, 500 ml beakers * Distilled water * Cotton * Test tubes * Spatula * Onion * Ethanol (70%) * Filter paper * Table sugar (sucrose) * Table salt (NaCl) * Potato EXPERIMENT 1 PART 1 Procedure: 1. The epidermal layer of an onion is scaled off carefully and placed on a drop of distilled water on the glass slide; 2. The glass slide is slowly lowered down on the epidermal layer using the needle; 3. The onion cells are examined through the…show more content…
A drop of blood is added into each test tube and they are left for 5 min.; 4. A drop of each solution is examined under the microscope. Results & Observations: Hypotonic solution | Hypertonic solution | Isotonic Solution | Distilled water | 4.0% (w/v) NaCl solution | 0.85% (w/v) NaCl solution | | | | | Discussion: The picture below shows how normal red blood cells look like: The first solution used is distilled water which is a hypotonic solution. In this situation, water will diffuse into the red blood cells causing them to expand and be round (as shown in the above results) and sometimes they may rapture as shown in the picture below: In a hypertonic solution, the red blood cells will shrink and be destroyed, as water diffuse out of them. Finally, in an isotonic solution there will not be any change in the shape of the red blood cells as there is no net movement of water in or out of the red blood cells. Conclusion: Type of Solution | Description | Examples | Effects on cell. | Isotonic | Has the same concentration of dissolved substances as the fluid in the cell. | 0.85% salt (normal saline); 5% dextrose (glucose) | None; cell in equilibrium with its environment. | Hypotonic | Has a lower concentration of dissolved substances than the fluid in the cell. | Less than 0.85% salt or 5% dextrose | Cell takes in water, swells, and may

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