Osmosis experiment Bronx community college biology 23, Assignments of Biology

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OSMOSIS

LAB REPORT

Prepared by: Brandy Baez, Daouda Nikiema, Laura De los santos, Tailia Morales.

Professor: Neville Crick

Subject: Biology

Date: 03/26/

Introduction: Osmosis is vital to cell health. Solvent molecules—usually water—are transferred across a semipermeable membrane from a region with lower solute concentration to one with higher concentration. This movement balances solute concentrations on both sides of the membrane to maintain the cell's internal environment. Understanding osmosis is important because it affects waste elimination, nutrition intake, and cell turgidity. Unbalanced osmotic conditions can cause cell swelling, bursting, or shrinking. As a model membrane, dialysis tubing will help us study osmosis in our experiment. Like cell membranes, dialysis tubing is semipermeable and restricts some molecules by size and charge while allowing others through. Before starting the experiment, understand isotonic, hypertonic, and hypotonic solutions. Isotonic solutions have cell-like solute concentrations. There's no net water movement across the membrane. A hypertonic solution forces water out of the cell, which may shrink it due to its higher solute concentration. However, water enters a hypotonic solution, which has fewer solutes than the cell and may inflate or explode it. We expect our experiment to show a hypotonic solution inside the dialysis tubing. We expect water to enter the tubing through osmosis, resulting in a net gain of water and an increase in tubing mass over the experiment. This experiment will examine how osmosis affects a model membrane to learn how cells maintain osmotic equilibrium in various settings. Materials and methods: We investigated the movement of substances through diffusion in this experiment by using a dialysis bag as a semi-permeable membrane. Similar to biological membranes' selective

75.4 grams, indicating that water was moving from a greater concentration inside the tube to a lower concentration inside the dialysis bag. This phenomenon showed a hypotonic solution in which the cell was filled with water, which may have caused cell lysis. Time 0 minutes 15 minutes 30 minutes 45 minutes 60 minutes Weight(g) 55.8g 63.8g 67.4g 71.5g 75.4g Conclusion: The experiment investigated osmosis using a dialysis bag model as a cell membrane representation. The hypothesis was that water would swell the bag due to osmosis, and the weight would increase over time. The results confirmed this hypothesis, with a consistent increase in the bag's weight indicating water movement. The results support the concept of osmosis as a passive mechanism of membrane transport, where water molecules move from higher concentration to lower concentration. However, the experiment only investigated osmosis in a hypotonic solution. Future experiments could explore hypertonic and isotonic solutions, a wider range of solutes and concentrations, and multiple trials to enhance reliability. The

experiment provides valuable insights into osmosis and lays the groundwork for further exploration in this area.