investigating osmosis - page 1
Keywords: osmosis
By hiimchinese on 26/11/2011
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 1 of 17 pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Aim: To investigate how different molar sucrose solutions, affect the rate of Osmosis within plant tissue!
Osmosis is the term applied to the diffusion of a solvent across a partially-permeable membrane from a region of low solute concentration to a region of high solute concentration. The solvent in this case is the water molecule, whereas the solute is the sugar molecule. The partially permeable membrane of the plant cell is only permeable to the solvent, not the solute, because of the difference in their sizes. The water can seep through, whereas the sugar molecules cannot, as their size is greater than the openings in the cell membrane. It is because of this, which causes a chemical potential difference on each side of the membrane that causes the process of diffusion to occur. In this, there is a random movement of the water molecules in both directions across the membrane and also a net movement of water into the region containing more solute. In both cases, the water molecules move through the membrane through their concentration gradient.
Osmosis is the process by which living cells intake or give out water as per their requirement. Without it all the biological processes would get ruptured. Without it there will be no plants as water is necessary for them which they transfer cell to cell through the process of osmosis.
Without plants there will be no organism as they are the primary producers of our food web.
However, most animals that live in the sea have around the same solute concentration with their cells as that of the sea. Therefore, their water balance is generally no problem which allows water molecules to enter and exit their body at the same rate. Land animals however, lose water constantly to their surrounding through: sweating, panting and urination. Consequently they must continuously drink water to maintain this balance. Osmosis is a fundamental process as it enables cells to quickly obtain water.
In this investigation, the intention is to observe how the effect of changing the solute concentration outside plant tissue (potato cylinders) affects osmosis. The investigation will begin with a preliminary which will allow for me to improve my execution and control of the experiment whilst also enabling me to find an appropriate range and number of repeats. Measuring the rate of Osmosis is extremely difficult however, I have done this by see the change of weight that occurs to the
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