Diffusion Across a Membrane: Size Matters

John Brennan Garner, Katy Ewing, Lauren Flynn, Michael Cobbs


Different substances can diffuse through a membrane at different rates, which poses the question of why this is the case. The first artificial cell was produced in 1964, but developments in synthetic biology led to the production of the first artificial membrane in 2011 (Chang, 1964; Staff, 2012). It has just recently become possible to perform new tests on this subject with the use of these artificial membranes, in this case dialysis tubing (French, 2014). We decided to use dialysis tubing to model a semipermeable membrane in order to test the rate of diffusion of different particles. We ran an experiment in which multiple trials were conducted to test the rate of diffusion of sodium chloride, starch, and glucose. This research could provide an explanation as to why different particles diffuse at different rates

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French, D. 2014. Investigating Biology: A Laboratory Resource Manual. 2014 edition.

Fountainhead Press: Fort Worth.


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