Biology investigation osmosis

Biology investigation

Osmosis

For this investigation we are going to find out whether potato chips placed in a range of different concentrated sugar solutions increase or decrease in mass.

Background knowledge

Osmosis is the passage of water molecules from a weaker, dilute, solution into a stronger, more concentrated, solution through a semi permeable membrane.

Each cell in a leaf is surrounded by a membrane, which separates the contents of the cell from the outside. The membrane has tiny holes in it, which allows small molecules only to pass through it.

As in the diagram, we have a weak dilute solution on the left and a stronger concentrated solution on the right. To even out the solutions a semi permeable membrane allows small water molecules to pass through it from the dilute to the concentrated solution.

Turgidity and Flaccidity

When plant cells are placed in water, the water enters the cells.

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English: A pile of potato chips. These are Utz-bra...

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As water enters it makes the cell swell up and eventually the cell contains as much water as it can hold and becomes turgid. If a cell is placed in a more concentrated solution water molecules leave the cell, making the cell lose its shape and weight and the cell becomes flaccid.

Turgid-

Flaccid-

Prediction

Due to my background knowledge of Osmosis I predict that the chips place in the more dilute solutions than others will gain the most weight from taking in a lot of water. I also think that the chips in the more concentrated solutions will decrease in weight and look shrivelled and flaccid.

I predict that my final graph will look like this: -

Pre test

I am going to do a pre test to make sure that when the final test takes place everything is fair.

In this pre test I am going to...