• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

the movement ofwater molecules only across a membrane. The water molecules willcontinue to diffuse across the membrane until equilibrium betweenconcentrations is established.

Extracts from this document...

Introduction

the movement of water molecules only across a membrane. The water molecules will continue to diffuse across the membrane until equilibrium between concentrations is established. Osmosis takes place in both plant cells and animal cells. Animal cells do burst in pure water. The cytoplasm inside the cell is quite a concentrated solution of proteins and other large substances. Therefore osmosis will take place between the cell and the surrounding fluids via the partially permeable membrane (the cell membrane). The cell will soon burst because of the swelling from the increase in water. Plant cells do not burst in pure water, though, because they have a cell wall that is fully permeable so osmosis does not take place across it. It is bypassed and osmosis takes place between the cell membrane in the same way as an animal cell, but with the resistance of the strong cellulose of the cell wall to keep the cell from bursting. When a plant cell is pushing out against the cell wall (like an inflated football) ...read more.

Middle

With regard to the osmosis, it will be taking place across cell membranes in the potato. The cells in the potato will be similar to the plant cells explained previously in terms of how osmosis occurs. Therefore I predict that water will diffuse into the potato if it is put into pure water. Also I expect water to diffuse out of the potato if it is put into a very concentrated sucrose solution. This is because there must be a considerable amount of water in the potato cells already seeing as a potato is a root vegetable and absorbs water into the ground. The sucrose concentration of the potato will be found when the potato is put into a concentration of solution in which no osmosis or diffusion of water takes place. From my own general knowledge I know that the water content of potatoes is approximately 70%. This is a notorious quantity of water found in nature e.g. the composition of humans is 70% water, the composition of the Earth is 70% water etc. ...read more.

Conclusion

To make the concentrations I used the following proportions: 1.0M Sucrose Solution (ml) Water (ml) Resulting Concentration 1 10 40 0.20 2 12 38 0.24 3 14 36 0.28 4 16 34 0.32 5 18 32 0.36 6 20 30 0.40 I made the solutions by using pipettes to measure the sucrose solution in one beaker and the water in a second beaker, then mixing both in a third beaker with a stirrer. With another pipette I put 10ml of each concentration into two test tubes so that there were two tubes with 0.2M, two tubes with 0.24M etc. I measured the mass of the potato cylinders and recorded the values, before putting the cylinders into the solutions, one cylinder in each test tube. I put labels on each tube to show which tube contained which concentration so that there was no error in mixing up the results. After leaving the potatoes for 24 hours (probably sufficient time for osmosis to take place) I drained away the solutions from the tubes, took out the potato cylinders and reweighed them, recording the new values next to the previous ones. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. Osmosis is defined as 'the movement of water molecules from an area of high ...

    For example the age, species e.g. King Edward, size and any imperfections in the potato can be kept to a minimum. 3: Stop the evaporation of any of the molar solution. This is because if the sugar solution evaporates past the level of the of the potato then the potato

  2. Looking at how concentration affects the movement of water particles through a partially permeable ...

    Water will move into plant cells by osmosis. * The cell membrane of the plant cell acts as a partially permeable membrane. * The cell sap inside the vacuole is a strong solution. * Water passes into the plant cell by osmosis.

  1. Osmosis is defined as the movement of water molecules across a partially permeable membrane ...

    The greater the concentration of water in the external solution the greater the amount of water that enters the cell by osmosis. The smaller the concentration of water in the external solution the greater the amount of water that leaves the cell.

  2. Osmosis is the passage of water molecules from a weaker solution into a stronger ...

    They will then be measured using a Vernier calliper (named after Pierre Vernier (1580-1637), a French mathematician) and cut to 50 mm in length. Each of these pieces will then be weighed (so that there is something to compare the results to)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work