Investigation of Osmosis in Plant Cells

Investigation of Osmosis in Plant Cells

My aim is to investigate osmosis in plant cells. I will do this by

carrying out an experiment to find out the percentage increase or

decrease in mass (grams) of potato tube, placed in varying

concentration of glucose.

Background Information - The theory of Osmosis.

Osmosis is a special case of diffusion that involves water. It is the

movement of water molecules across a partially permeable membrane from

a region of high water concentration to a region of low water

concentration until equilibrium is reached. This means that only water

molecules can pass through the partially permeable membrane due to it

being small enough to fit through. Bigger molecules such as glucose

would not be able to get through. Also Osmosis makes plant cells swell

up or turn turgid when the cell is placed in a solution containing a

higher concentration of water, or shrivel up when placed in a low

concentration of water.

Apparatus.

· Cutting tile - to cut the potato on

· Knife - to cut the potato

· 25cm Measuring cylinder - to measure the solutions

· Distilled water

· Sucrose

· Potatoes

· Tissue paper - to dry the potatoes after the osmosis takes place

· Balance - to weigh the potatoes

· Cork borer - to cut out potato cylinders

Prediction.

In the distilled water, I believe that the water is more concentrated

surrounding the potato and therefore the water should transfer from

the water to the potato, making the potato bigger in size, and heavier

in weight. The potato tissues, being surrounded by a weak solution,

will be most likely to swell up and become turgid, taking in all the

water it can possibly take in, until the amount of water inside the

potato surrounding the potato has reached equilibrium.

My prediction for this experiment is that, due to the difference in

the different concentrations, I believe that the weight of the potato

will start decreasing when it is tested on 0.