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

Investigate the effects of different water potential sucrose solutions, on the size and weight of potato cylinders over the period of 48hours.

Extracts from this document...

Introduction

Osmosis in Plant Cells Aim: To investigate the effects of different water potential sucrose solutions, on the size and weight of potato cylinders over the period of 48hours. (Plant Cells) Prediction: From my background knowledge I predict that as the concentration of the sucrose solution that the potato cylinder is placed in increases, the size and weight of the potato cylinder will decrease over the period of 48hours, and vice versa, if sucrose solution concentration decreases, the potato cylinder should swell up and its size and weigh will increase. These predictions have scientific explanations. When a potato cylinder is placed in a high concentration sucrose solution where little water or no water at all is added, the potato cells under go a process called plasmolysis. Plant cells, in this case potato cells have a thick cell wall which is freely permeable and supports the cell; inside this cell wall is the protoplast which has a partially permeable plasma membrane. When the concentration of the surrounding solution in this case sucrose solution is high, it means that the solution potential surrounding the cell has very low water potential compared to the potato cell. (for plant cells water potential is a combination of solute potential and pressure potential which can be expressed as ? ...read more.

Middle

Apparatus: 1. Measuring Cylinder (25ml) 2. Syringe (5ml) 3. 5 Test tubes 4. Distilled water (25ml) 5. Sucrose solution 1 molar Concentration (25ml) 6. Beaker (50ml) 7. 5 potato cylinders (30mm width) 8. Scalpel 9. Electronic balancer 10. Accurate ruler for measurement (in mm) 11. Foil and tissue paper Method: * First stage is to cute the 5 potato cylinders accurately to width of 30mm using ruler and scalpel * We then measure the potato cylinders weight by placing each on the electronic balancer and recording the data * Second stage is to create the 5 different concentration solutes to pour into each test tubes by using the information on the table below: Test tube Concentration of sucrose solution Volume of distilled water (ml) Volume of 1molar sucrose (ml) 1 0 10 0 2 0.25 7.5 2.5 3 0.50 5 5 4 0.75 2.5 7.5 5 1 0 10 * After creating the solutions (10ml each), then we add each potato cylinders to each test tubes containing sucrose solution in order which I recorded their weight by * Then Secure each test tube by raping the end by aluminium foils * The test tubes are placed in a test tube holder and left for period of 48hours * After 48hours take out each potato cylinder in order and measure their size and weight and record them on the results table and calculate the differences in weight and size in mm and grams. ...read more.

Conclusion

Looking at my 0.5molar sucrose solution results, we can see a +0.1 g increase in weight, but looking at difference in size, there is a -1 mm decrease in size. This can be simple mistake in measurement using apparatus such as ruler and electronic balancer. Therefore to provide more accurate results and fair test, much more attention and concentration is required. * Using ruler to cut each potato cylinder is not very accurate since we have to rely on accuracy of human eyes which is simply not enough. In order to have exact equal size potato cylinders, mechanical machine cutters can be used. * Other factor which may have affected my results is the electronics balancer. The electronic balancer needs to be on a fully flat surface before use, because if it is moved to a different place, different results maybe given since the flatness of different surfaces are differ. * To produce different concentration solutions of sucrose, we again have to rely on our sight accuracy when using measuring cylinders to mix distilled water with sucrose (1molar). Simple inaccuracy may have effects on our results so to make this a fair test; more accurate apparatus which have much more accurate measurement can be used. Amin Shahiri 12AW Biology Osmosis Assignment 1 ...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. Marked by a teacher

    To investigate how varying the concentration of sucrose solutions affects the rate of osmosis ...

    3 star(s)

    my results, I think that my experiment was successful as I found out that changing the molarity of a solution does affect the rate of osmosis. I found the results using 0.125M solution as surprising though. This is because I did not expect to see an increase in the turgidity of the potato cylinders immersed in this solution.

  2. Investigating the cellular water potential of potato cells.

    I found that 20cm� would suffice in covering all three of the potato samples fully and would allow for any gain in size of the samples, so that they would still remain fully submerged. This also means that there is plenty of solution to allow for optimum osmosis to occur within the potato samples.

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

    This will allow us to see whether osmosis has taken place, and to what extent. "X The volume of the solution that the potato chips are kept in must be fair. The must be totally covered in the solution, and the amount of solution will be kept the same because all the potato chips are the same size.

  2. Osmotic pressure

    Time I will also keep this variable constant. Time is a very important factor as it takes time for molecules to reach the iso-osmotic point. If the potato chips were submerged in the sucrose solution for a small amount of time, the change in mass and length would be

  1. Investigating the Water Potential of Potato Cells

    be made up in 6 test tubes using a 20ml syringe for adding the water and 5ml syringe for adding the sucrose. 3. Next I will weigh each potato piece I have cut using a balance. 4. I will now place one piece of potato to each test tube for a period of 20 minutes.

  2. Investigating the effects of osmosis on potato cylinders.

    However, in one case there was no change in length. This is because the concentration of water in the solution equalled the concentration of water in the potato cells - i.e. the cells were Isotonic. In the case of the potatoes that grew, the higher the concentration of water there was, the longer the potatoes grew.

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