Biology Coursework No.1- Osmosis

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Biology Coursework No.1- Osmosis


The aim is to investigate the effect of changing concentrations of glucose mixture in water in potato chips using osmosis.


* In the pure water (0% glucose) solution, I believe that the potato chip's mass would increase.

* In the 2% glucose solution, I believe that it will also gain weight, but not as much compared to the 0% glucose solution.

* In the 4% glucose solution, I too believe that it will gain weight, but again, not as much as the 0% or 2% glucose solution.

* In the 6% glucose solution, I believe that the potato chip will remain the same weight.

* However, in the 8% solution, I believe that the potato chip will loose weight.

* Similarly, in the 10% solution, I too believe that the potato chip will loose weight

* . However it will be more compared to the 8% solution.

I think this will happen because I am guessing that the isotonic point( see above) for the potato chip is somewhere between 4% and 8 %.The potato chip in 4% will have a lower water potential than the water around it and will therefore gain water due to osmosis.


Osmosis is the passage of water (using diffusion) from a region of high water potential through a semi-permeable membrane to a region of low potential until the solution reaches it's isotonic point. The isotonic point describes the point in which osmotic pressure is equal and osmosis stops.

(Diffusion is the movement of molecules from an area of higher concentration to that of a lower concentration. Once the particles have reached equilibrium, there is no longer any net movement because a gradient no longer exists.)
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Semi-permeable membranes are very thin layers of material (cell membranes are semi-permeable) which allow some things to pass through them but prevent other things from passing through.

Cell membranes will allow small molecules like Oxygen, water, Carbon Dioxide, Ammonia, Glucose, amino acids, etc. to pass through. Cell membranes will not allow larger molecules like Starch, protein, etc. to pass through.

A region of high concentration of water is either a very dilute solution of something like pure water. In each case there is a lot of water: there is a high concentration of water.

When ...

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