FREE ESSAY ON GLUCOSE CONCENTRATIONS ON OSMOSIS

GLUCOSE CONCENTRATIONS ON OSMOSIS

Studying the Effect of Various Glucose Concentrations on Osmosis in a Potato
Osmosis is the process in which water particles move from an area of high water
concentration to an area of low water concentration through a semi-permeable membrane
until the concentrations are equal. 
Osmosis has the same basic theory as diffusion. Particles are moving from an area where
they are in great concentration to an area where they are in low concentration until the
concentrations are the same. Osmosis is this movement of water particles and the
particles must move through a semi or partially permeable membrane (a membrane that lets
some things through but not others). An example of this type of membrane is a cell wall,
like in a potato. Osmosis occurs when two things occur. One is if the cell has no water
in it or has less water then the solution it is placed in. If this is the case then water
will go from the solution, for it is the area of high water concentration, into the cell,
for this is the area of low water concentration. If the cell has no water within it the
cell is flaccid. As the water passes through the cell membrane, the cell fills with water
and becomes turgid. Once the cell becomes turgid, no more water can enter the cell and
osmosis stops. 
The other incident that can happen for osmosis to occur, is when the concentration of
sugars or other minerals in the cell is different then that of the solution it is placed
in. This is because the amount of sugar in the water either in the cell or in the
solution is going to change the water concentrations as well. Whichever solution, either
in the cell or not, contains a higher sugar concentration will have a lower water
concentration. If the solution in the cell contains more sugar, salt or other minerals
then the solution it is placed in, then it will have a lower water concentration. This
will cause water from the external solution to pass through the cell's semi-permeable
membrane into the cell to make the two concentrations equal. Osmosis would also occur if
the external solution contained more sugar then the solution inside the cell. In this
case, water from inside the cell would pass through the cell's semi-permeable membrane
into the external solution making the concentrations equal.
If we relate osmosis to the weight of our potato, we can see that if the potato cells
lose water the weight of our potato decreases and if the potato cells gain water then the
weight of our potato increases. We can determine the concentration of our potato by
knowing this. If the potato increases in weight, then the solution outside the cell has a
greater water concentration then that which is inside the cell. We know this because
water must have entered the cell through its membrane because the water was moving from
an area of high water concentration (the external solution) to an area of low water
concentration (inside the cell) until the concentrations were equal. If the potato
decreases in weight, then the solution inside the cell has a greater water concentration
then that which is outside the cell. We know this because the water must have left the
cell through its membrane because the water was moving from an area of high water
concentration (the inside of the cell) to an area of low water concentration (the
external solution) until the concentrations were equal.
Diagram of Apparatus
Apparatus
Potato 
Glucose Solution
Boiling Tubes and Rack
Scale
Method
1. Set up apparatus as shown in diagram.
2. Cut potato squares into equal lengths and widths. My potatoes were 3cm long and 1cm
wide.
3. Number or mark each potato so that they can be identified 1 through 16.
4. Dry and weigh each potato piece and record your findings.
5. Put 4 of your potatoes in a solution of 1 molar glucose, 4 in a solution of .6 molars
of glucose, 4 in a solution of .4 molars of glucose, and 4 in 0 molars of glucose or
water. They are all placed in boiling tubes. Use 10 cm of solution.
6. Leave them to sit for 20 minutes.
7. Dry and reweigh each potato.
8. Record their new weight and make graphs.
9. Repeat three times for averages.
Note: Due to the short time we had to work on this experiment, we were unable to repeat
the experiment three times. Therefore we only have one set of results.
Fair Test
To make this experiment a fair one, there were many things we had to ensure happened.
 Repeat the experiment three times and take averages.
 Use the same volume of glucose solution even though it is not in the same
concentration. I used 10 cm of glucose solution.
 Use the same size pieces of potatoes. Mine were 3 cm by 1cm.
 Let them sit for the same amount of time before taking them out to be weighed. I
left them for 20 minutes.
 Dry the potatoes before you weigh them. This will remove the excess water from
the surface of the potato hence giving you a more accurate result.