• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19
  20. 20
    20
  21. 21
    21
  22. 22
    22
  23. 23
    23
  24. 24
    24

Potato Chips

Extracts from this document...

Introduction

Skill Area P: Planning Aim: To investigate the influence of the concentration of the surrounding solution on potato tissue Background Information: Osmosis is a special type of diffusion. It is the diffusion of water molecules through a selectively permeable membrane, it goes from a place of a high water concentration to a place of low water concentration to try and make the two concentrations equal - this is called a concentration gradient but in the case of water it is known as water potential. Cells placed in distilled water, absorb water by osmosis. This happens because the cells contain dissolved chemicals and therefore they have a lower water potential than the surrounding liquid. Eventually the cells stop absorbing the distilled water even though the concentrations inside and outside the cell are not equal. This is because the cell wall of the cells become stretched and prevents any more water entering. The cell is said to be turgid. In a turgid cell (left diagram) the vacuole and cytoplasm swell causing the content of the cell to push against the cell wall. The cell wall resists this pressure and pushes back. The cell cannot take in any more water so consequently osmosis stops. In a concentrated sugar solution the cells lose water by osmosis, as there is a higher concentration of water in the cell, water moves out of the cell by osmosis into the sugar solutions. This causes the cell to become limp; this is called a plasmolyzed or flaccid cell. In a plasmolyzed cell (right diagram) placed in a concentrated sugar solution, the cytoplasm and sap vacuole shrink causing the cell content to pull away from the cell wall. Prediction: I predict that as the concentration of the sugar solution around the potato chip decreases, the size of the potato chip will increase. I have come to this conclusion due to previous work I have done on osmosis in class. ...read more.

Middle

Therefore backing up my prediction and reasoning behind it. Skill Area O: Obtaining Evidence Preliminary Work For my preliminary work I used a 30mm potato chip. Preliminary work is important to do so that you can foresee if any complications could arise whilst doing your experiment. Complications that may occur are; the potato chip getting wedged in the test-tube, if the solution would overflow when the potato chip was added, that osmosis might not occur in the allowed time etc. My original plan was that the potato chips would be left in their solutions for thirty minutes and then removed. This however proved to be too short a time for osmosis to occur in any huge amount. This can be seen in the table below. Concentration Before Length (mm) After Length (mm) Average Change in Length (mm) Difference in Length against 30mm 0% Test 1 30 30 30.0 0.0 Test 2 30 31 30.5 + 0.5 5% Test 1 30 28 29.0 -1.0 Test 2 30 35 32.5 +2.5 10% Test 1 30 32 31.0 +1.0 Test 2 30 34 32.0 +2.0 20% Test 1 30 27 28.5 -1.5 Test 2 30 27 28.5 -1.5 30% Test 1 30 29 29.5 -0.5 Test 2 30 28 29.0 -1.0 This table shows me that in thirty minutes the results produced are too minute to conclude my prediction. Modifications As a direct result of the preliminary experiment I have learnt to increase the time needed for osmosis. This is because the results I obtained from my preliminary work did not show a clear trend, this could be because osmosis was still occurring. Therefore I felt it appropriate to increase the time limit that the chips are in their solutions in my plan. Other than this I did not need to change any other part of my plan. Modified Method: 1. Core five potatoes chips using the potato corer. ...read more.

Conclusion

The experiments produced results that were all convincingly similar with one or two anomalies. I have accounted for these anomalies in my analysis. My results show that I was consistently accurate with my experiments as there is little chance that I could have completed every experiment incorrectly. My experiment was suitable because it provided me with the information I needed to confirm my initial predication (which can be found on pages 2-3). There are however places and ways that errors could have occurred. First starting with the concentration. It is possible that when I made-up my sucrose solutions they were not accurate. They might not have been accurate because I could have used the wrong amount of distilled water - which should have been equal to 100cm� or I might have measured the amount of sugar incorrectly. Also a major factor was the cutting of the potato chips. I could have easily left a larger surface area on one and not on the others. Therefore one potato chip would be at an advantage as a larger surface area induces more osmosis to occur. One way to avoid this would be to use complicated machinery to weigh and cut the potato; although this would have been beneficial, this wasn't practical. So by just taking extra time and care with the cutting would make the experiment more accurate. Logically I could have done more work. I could have repeated the experiment more times to gain a more accurate average. Also, if I had tested a wider range of concentrations it may have made my results more accurate. Also I could experiment with exposing the same weight pieces, but with different surface areas. This would be helpful to do, as it would show if surface area greatly affects osmosis. If I were to repeat the experiment again I would go to a higher range of concentrations as explained in my conclusion on page 22. I would also use concentrations with smaller differences so I could plot a more accurate graph. Biology Coursework Francesca Tate 1 Mrs Dolan 10D ...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

    Osmosis in Potato Chips

    5 star(s)

    5.07 4.21 20 7.50 6.00 2.13 1.73 1.33 2.80 20 7.47 6.83 4.82 6.29 1.07 4.75 40 7.82 0.00 0.51 0.26 1.66 0.61 1.80 40 7.80 0.13 0.26 1.28 7.56 2.31 40 7.85 0.00 0.00 1.53 8.41 2.48 50 8.01 0.00 -0.25 -7.74 -7.24 -3.81 -3.44 50 7.93 -0.25 0.00

  2. Marked by a teacher

    Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.

    5 star(s)

    a ruler shall only show a change in how long the potato chip is. I shall record each weight to two decimal places as this is accurate. There is no need to show the results to three decimal places. This would also reduce the accuracy of the points plotted on

  1. Marked by a teacher

    How does the concentration of a sucrose solution affect the rate of Osmosis in ...

    5 star(s)

    axis, as this shows me the point at which the two solutions inside and outside of the potato were the same, i.e. Isotonic. Potato Cell Beaker These two solutions are isotonic, as they have the same ratio of sucrose molecules to water molecules.

  2. Marked by a teacher

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

    3 star(s)

    I did this by carefully measuring their lengths to the nearest millimeter. I measured the length of each cylinder twice to ensure that my measurements were correct. I repeated this process to measure the lengths of the cylinders after having immersed them in the various solutions.

  1. Investigating the cellular water potential of potato cells.

    x 100 = -18.4 0.8 -0.15 (-0.15/0.50) x 100 = -30.0 Graphs The graph that shows 'percentage change in mass' plotted against the 'concentration of sucrose solution' shows that as the concentration of the sucrose solutions increases, the percentage change in mass moves from highly positive to highly negative.

  2. To investigate osmosis in potato chips when being placed in sugar solutions of different ...

    When the cell loses water it shrinks and becomes flaccid, when it gains water it increases in size and becomes turgid. (P8B) Background information Osmosis is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration.

  1. How Does The Concentration of a Sucrose Solution Affect The Mass of a Potato ...

    It appears to occur when the solution's strength is just under 0.5 Molar at around 0.48, I.E this is the point where the line of best fit cuts the x-axis. Therefore around this point the solutions inside and outside the cells have the same concentration.

  2. Aim: To find out the effect of altering the concentration of sugar solution on ...

    More importantly I now know what a suitable range of concentrations of sugar solution to use in the investigation. In the main investigation I will be testing six different concentrations of sugar solution. The sugar solution is to be made up by dissolving a certain mass of sugar in water and the solution made up to 100ml.

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