Diffusion Biology Essay Papers

The purpose of this lab was to observe the rate of osmosis and diffusion, as well as the effect of molecular size of the particles on this rate. Part I of the lab was a demonstration of osmosis and diffusion, that dealt with raisins in different liquid environments, each with a different concentration of sugar. Part IV of the lab was using the same idea as the demonstration, by putting objects in different concentrations of a substance; in this case elodea leaves in salt water. In both cases, the objects in a greater concentration of the substance were stripped of their water. However, where there was a little or no concentration of sugar or salt, the objects did not lose their water, and in the case of the raisin, became saturated with excess water. Part II of the lab dealt with the rate of osmosis, and how molecular size was a factor on it.

The purpose was to see how easily molecules of smaller diameter, which were starch molecules, would pass through an artificial membrane, as opposed to how difficult it would be to pass through in the case of larger molecules, which were IKI molecules. Results were that the smaller substance passed though the membrane easily and rather quickly, and the larger substance did not penetrate the membrane whatsoever. Part III of the lab was to view the effect of molecular size on the rate of diffusion. Two substances, both being of different molecular size were placed in the same environment. Results were that the substance with the smaller molecules, diffused farther away from where it was placed than did the substance of greater molecular size in the same amount of time.

The title of this lab is 'Osmosis and Diffusion.' Both these terms deal with the...


Essay about Diffusion Lab Report

2627 WordsNov 5th, 201011 Pages

Abstract:
The importance of this computerized simulation study was to gain an understanding of the processes that account for the movement of substances across the plasma membrane, and to indicate the driving force for each. This may also be applied to the study of transport mechanisms in living membrane-bounded cells. Also, understanding of which way substances will move passively through a deferentially permeable membrane depending on the concentration differences. We used PhysioEx software to examine diffusion. In these experiments we used different sized membranes as well as NaCl, urea, glucose, albumin, powdered charcoal, and KCl. The step by step process was used by the software so that we could see the different kinds of…show more content…

This is unlike the rest that are the diffusion of molecules. In pinocytosis a bit of infolding plasma membrane surrounds a very small volume of extracellular fluid containing dissolved molecules. These “cell drinking cells” are also called fluid-phase endocytosis. The fuse with endosome occurs when the droplet enters the cell. Pinocytosis is a routine activity of most cells, affording them a nonselective way of sampling the extracellular fluid, unlike phagocytosis. Phagocytosis is engulfing of foreign solids by cells. Experiments were conducted in order to gain a better understanding of a cell’s selectively permeable membrane and the passive processes of simple and facilitated diffusion. The purpose of this experiment was to make observations based on the computerized simulation providing information on the passage of water and solutes through semipermeable membranes, which may be applied to the study of transport mechanisms in living membrane-bounded cells. We hypothesized that when the sucrose concentration will change, the mass will also change.
Materials and Methods:
We used PhysioEx software to examine diffusion.
Activity 1: Simulating Dialysis (Simple Diffusion)
Results:
Dialysis Results ( Average diffusion rate in mM/min) | Solute | Membrane (MWCO) Pore size | | 20 | 50 | 100 | 200 | NaCl | ---- | 0.015 | 0.015 | 0.015 | Urea | ---- | ---- |

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