Cell Membrane Transport

Topics: Cell membrane, Diffusion, Molecular diffusion Pages: 12 (3349 words) Published: July 26, 2012

In this Lab the students dealt with Osmosis, movement of water molecule or solvent from a high concentration to a low concentration, through selective permeability, a protective barrier that provide some particle the 'direct' passage in and out of the plasma membrane ( Lacerda L.2011) Allowing some molecules enter and exit the cell membrane, to create a balance in concentration inside and outside of the cell, by doing so the cell often become hypotonic, where the concentration outside the cell is higher than the concentration inside the cell, therefore causing the swelling of that cell. When cell was placed the the deionized water environment, hypothesis was made that the cell will become hypotonic and swell up as the time increased.

“Diffusion is a passive process in which the random mixing of particles in a solution occurs because of the particle's kinetic energy “(Allen C. 2006), and is subjected to detect the presence of each of the substances given in the biochemical testing, the increase in temperature, and different reagent used are some aspect that could cause the difference of diffusion in certain solution. It was clear that the protocols Glucose, Albumin, NaCl, and Starch would be tested positive in the cytoplasm solution through diffusion, meaning they are present, as the report directed, and hypothesis was made that the same protocols would be tested negative, meaning not being presence in the environment.

Rate of diffusion was discussed in the Diffusion in Gel, Liquid, and Air. The change in temperature affects the rate of diffusion in Gel and Liquid. The hypothesized was made that the warmer the temperature is, the faster the diffusion, because heat provide the molecules with more kinetic energy which is the energy of motion, while the lower the temperature is, the slower the diffusion, because energy is not provided, while Diffusion rate could also be slow down because of the increase in viscosity in the environment that surrounds the substance (Novak I.L. 2009), such as the diffusion in gel when compared to the diffusion in liquid, gel is a much more viscous substance, it is harder to diffuse through Gel than it is to diffuse through liquid.

For diffusion in Air, hypothesis was made that if the person is further away from the point of origin where the fragrance was sprayed, the longer it will take them to smell the scent, and the closer a person is to the point where the fragrance was sprayed the faster and stronger the scent travels.

Filtration is a way of separating a solute what was being dissolved form the solvent what was dissolving (Valderama-Bravo C. 2009), that also demonstrated the usage of selective permeable membranes, we hypothesized that through filtration, the charcoal that was mixed in with the distilled water and copper sulfate crystals would not pass through the layer of filter paper, and that as the time for distilled water mixed with the copper sulfate crystal starts to filter increase, the number of drops going down the funnel would decrease in a steady motion. The purpose of this whole experiment conducted, allowed the students to better understand and identify Osmosis, Diffusion and Filtration. As we conducted through each experiment and learn the change in each protocols, the different reaction for the same substances with different reagent, gave us a closer look at some of the factors that could cause a change in results in osmosis, diffusion and filtration.

Methods and Material

Methods and Materials: Cell Membrane Transport. Protocol – Department of Biology, Zoology Laboratories. 2011. Available from: Texas Woman’s University, Denton, Texas.


Table 1: Diffusion of Cell Cytoplasm in the Environment

|Cell weight Before it was put into the environment |Cell weight after it was put into the environment for 1 hour | |5.80 g...
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