Diffusion Across Biological Membranes: a Simulation
Diffusion across Biological Membranes: A simulation
Introduction
Diffusion is the process by which collisions between molecules cause to spread apart. This movement is described as movement from an area of greater concentration to an area of lower concentration. Hence, diffusion continues until the molecules are equally distributed. This is to ensure that molecules have reached a state of equilibrium. Diffusion occurs spontaneously, no energy is involved.
In cells, Diffusion occurs through cell membrane which is selectively permeable. This means that some molecules can pass through the membrane while other molecules cannot. Molecules that move across the membrane through diffusion are either hydrophobic or small and uncharged. For example, H2O, O2 and CO2. On the other hand, those molecules which did not make through the membrane such as large polar molecules must be transported through protein mediated mechanisms to cross the membrane.
Hence, this experiment is focused on diffusion and required to create a own model cell by pouring distilled H2O, starch, iodine and glucose in tied dialysis tubing to test for substance which diffuse through the membrane and which one could not due to its size.
Materials and Methods
Materials:
* Distilled H2O * Starch solution * Iodine solution * Glucose solution * Test tube (3-4/group) * Test tube rack * Marking tape * Benedict’s test solution * Hot water bath * Dialysis tubing: 1 inch flat width, pre-soaked * Dialysis tubing: 3 inch flat width, pre-soaked * Breaker * 3ml pipette
Methods:
Tract the substance
Step 1: Labeled 4 test tubes as Distilled H2O, Starch, Glucose and Iodine.
Step 2: Add 2ml of distilled H2O, Starch, Glucose and Iodine in the respective test tubes and add 2ml of Iodine indicator into all 4 test tube.
Step 3: Swirl the test tubes lightly to ensure the Iodine indicator and 4 solutions mixed well. Observed the colour change closely
Introduction
Diffusion is the process by which collisions between molecules cause to spread apart. This movement is described as movement from an area of greater concentration to an area of lower concentration. Hence, diffusion continues until the molecules are equally distributed. This is to ensure that molecules have reached a state of equilibrium. Diffusion occurs spontaneously, no energy is involved.
In cells, Diffusion occurs through cell membrane which is selectively permeable. This means that some molecules can pass through the membrane while other molecules cannot. Molecules that move across the membrane through diffusion are either hydrophobic or small and uncharged. For example, H2O, O2 and CO2. On the other hand, those molecules which did not make through the membrane such as large polar molecules must be transported through protein mediated mechanisms to cross the membrane.
Hence, this experiment is focused on diffusion and required to create a own model cell by pouring distilled H2O, starch, iodine and glucose in tied dialysis tubing to test for substance which diffuse through the membrane and which one could not due to its size.
Materials and Methods
Materials:
* Distilled H2O * Starch solution * Iodine solution * Glucose solution * Test tube (3-4/group) * Test tube rack * Marking tape * Benedict’s test solution * Hot water bath * Dialysis tubing: 1 inch flat width, pre-soaked * Dialysis tubing: 3 inch flat width, pre-soaked * Breaker * 3ml pipette
Methods:
Tract the substance
Step 1: Labeled 4 test tubes as Distilled H2O, Starch, Glucose and Iodine.
Step 2: Add 2ml of distilled H2O, Starch, Glucose and Iodine in the respective test tubes and add 2ml of Iodine indicator into all 4 test tube.
Step 3: Swirl the test tubes lightly to ensure the Iodine indicator and 4 solutions mixed well. Observed the colour change closely
References: http://www.sfponline.org/uploads/336/DiffusionLabReport.pdf http://faculty.buffalostate.edu/wadswogj/courses/BIO211%20Page/lectures/lab%20pdf 's/Diffusion%20lab%2006a.pdf http://www.studymode.com/essays/Diffusion-Through-A-Membrane-Lab-462261.html http://answers.yahoo.com/question/index?qid=20100615085037AAQJsXx http://www.indiana.edu/~nimsmsf/P215/p215notes/LabManual/Lab5.pdf