Diffusion Of The Plasma Membrane

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Introduction Diffusion is one of two passive process membrane transports that moves molecules from a region of their higher concentration to a region of their lower concentration and has a driving force of kinetic energy. Simple diffusion, which is what this experiment is about, occurs without the assistance of membrane proteins along the concentration gradient not using any energy from the cell itself—this is where the kinetic energy come into play. Instead, the energy is coming from the molecules constant motion. Once the solutes are dispersed evenly through the solution, equilibrium will occur and the movement will stop (PhysioEx9.1). The plasma membrane in a cell is the physical barrier and is in charge of determining what goes in and…show more content…
Keep in mind that the larger the MWCO, the larger the pores in the membrane are. The goal is to understand how solute concentration and different molecular weights affect the rate of diffusion. Materials: PhysioEx9.1 Computer Program Exercise 1 Activity 1 (Simple diffusion), 2 beakers, dialysis membranes with 20, 50, 100, and 200 molecular weight cut offs (MWCO), and deionized water. Methods: In this experiment, two beakers were used—the left beaker held the varying solutes and the right beaker held the deionized water. Placed in the middle of the two beakers was the dialysis membrane with various molecular weight cutoffs (MWCO), 20, 50, 100, and 200 MWCO. Four different solutes, sodium chloride, urea, glucose, and albumin, were tested in different trials during this experiment based on their molecular weight. Sodium chloride has a molecular weight of 58.44 g/mol, the smallest out of the four, so it was tested in the first trial with 20 MWCO. The left beaker was filled with 9mM of sodium chloride and the right beaker was filled with water. The barrier between the two beakers was dropped, allowing the solutions to have full access to the dialysis membrane. At the end of 60 minutes, the amount of solute that passed through the membrane will be able to be observed on the concentration display. After the amount is recorded, the beakers were flushed and the next solute was added. The second trial with the 20
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