Properties of a Selectively Semi-Permeable Plasma Membrane While Undergoing Diffusion.
This experiment will examine properties of a semi-permeable plasma membrane by investigating how different solutions react when placed in a dialysis tube surrounded by another solution. One dialysis tube is filled with starch and placed into a beaker containing iodine, while the second tube is filled with glucose and placed into a beaker of water. In the first tube, the iodine diffuses through the membrane into the dialysis tube. For the second tube, glucose diffuses out of the tube through the membrane into the water and water molecules diffused into the tube. This signifies that starch molecules were too large to pass through the membrane while the other substances were small enough. This reflects the semi-permeable nature of cell's membrane.
Key Words: semi-permeable, membrane, diffusion, osmosis, concentration gradient, homeostasis, isotonic, hypotonic, hypertonic.
Introduction.
The dependence of life processes on diffusion mechanisms could not be more prevalent. Diffusion occurs throughout the human body, and without it, cells and body tissue could not get important nutrients for survival, the eyes would dry out, and many medicines could not be absorbed into the body. According to Oklahoma City Community College (2015), diffusion is defined as "the movement of molecules from a high concentration to a low concentration, typically through a semipermeable membrane." The concept of diffusion describes the process by which cells exchange toxic gases for life-sustaining gases. It allows nutrients to enter the cell while keeping harmful molecules out of the cell. It also explains how nerve cells are able to send electrical signals to each other cells. Diffusion tells embryonic cells where to move and when to stop (Angeli, 2010). .
Additionally, the diffusion of water through a membrane is such an important process, that it has earned it's own term.