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

Investigation into the effects of osmosis on Potato cells

Extracts from this document...

Introduction

Investigation into the effects of osmosis on Potato cells PLANNING AIM The aim of this investigation is to find out the concentration of cell sap in potato tissue. Variables * Controlled-Starting length will be as close to 3.00cm possible, starting volume, which is 20ml also the same time the potato cells are kept in solution and same conditions for each cylinder. * Dependant-Length of potato cylinder (before and after osmosis has occurred). * Independent-Concentrations of solutions which are: (m) 0,0.1,0.2,0.3,0.4,0.5 Solutions Vol. Of glucose * 0.5 = M (0.5 = starting glucose concentration) Total volume 1) 0 * 0.5 = 0 M 20 2) 4 *0.5 =0.1M 20 3) 8 *0.5 =0.2M 20 4) 12 *0.5 =0.3M 20 5) 16 *0.5 =0.4M 6) 20 *0.5 =0.5M 20 20 Prediction I predict that this experiment will have different results throughout all the concentrations. Osmosis depends on two concentrations; outside (glucose solution) and inside (cell sap). I feel that my experiment will prove that osmosis has occurred meaning the water has moved form a high concentration to a low concentration. But. If the cell was already turgid when we measured it, the movement of water from a higher concentration to a lower concentration means we will find the potato cell will shrink as the solution has moved out. ...read more.

Middle

Other instruments which were the measuring cylinders - 10 ml & 25ml that are accurate to *-0.1ml & *-0.5ml respectively. This helped when I had to measure out glucose solution and distilled water. This all helped to get accurate results & a successful experiment. Strategy for results For my results for the experiment, I will make a table with concentrations down the left side and lengths of potato cells along the top. Then the percentage change in length down the right side. The title will be - -Investigation into the effects of osmosis on potato cells: Results. The graph that I will plot my results will have Concentration of glucose (M) on the X-axis and % change in length on the Y-axis. On this I will draw a best-fit line. Above the X-axis, the results are Hypotonic and below the X-axis the results are Hypertonic. But if the results are on the X-axis line, the result is isotonic meaning the concentration inside equals' concentration outside. Table and graph overleaf To find the percentage change in length, I had to use the following formula: final length - original length original length * 100 (1) 0M; 3.12 - 2.96 2.96 * 100 = 5.405% (2) 0.1M; 3.14 - 2.98 2.98 * 100 = 5.369% (3) ...read more.

Conclusion

This might be anomalous because maybe the volumes measured inaccurately or the vernier callipers were read slightly wrong. This means if there was a mistake it was because of human error. How suitable was my procedure? I feel my procedure was well suited to this investigation, because 0.25M (isotonic) fell in between 0.2M and 0.3M, meaning a perfect experiment. Also the apparatus was good enough for a successful experiment. Any changes to improve? I fell that there are many changes I could do to improve my experiment to get more accurate results. And they are: 1. Be more accurate when cutting the cylinders, try to be as close to 3.00cm as possible. If we had two different starting lengths e.g. 3.02cm and 3.12cm it would not be fair because 3.03cm chip has a greater SA: VOL giving it an advantage in terms of osmosis. 2. A third potato cylinder could be cut and put into the specimen bottle to increase accuracy in getting results. 3. A burrette could be used. These are accurate to 0.1ml, which would help when we are measuring out our solutions. 4. Also Digital Vernier callipers would be useful as we could just read off the measurement and possibly eliminate human error when measuring. Does the evidence support a firm conclusion? Yes, because 0.25M (isotonic result) corresponds with book value so this is encouraging. Five of my plotted values follow the pattern and only one is anomalous. ...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

Here's what a teacher thought of this essay

5 star(s)

*****
This account shows attention to detail and good use of scientific language. There are a few minor errors.

Marked by teacher Adam Roberts 01/05/2013

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

    Biology Coursework - Osmosis

    5 star(s)

    same variety treated in the same way, i.e.: have all been cut with scalpel, and skins removed. Temperature To ensure the temperature doesn't vary, I will perform all the experiments at room temperature.

  2. Marked by a teacher

    Potato / Osmosis Experiment.

    5 star(s)

    To help me discover the exact isotonic solution, I decided to do more readings in this area. The entire second set of readings was completed the following day, in exactly the same process previously described for the first set. Another reason for doing extra readings is that the more readings, the more accurate the results.

  1. Marked by a teacher

    Investigating Enzymes and the effects of different variables such as temperature on how they ...

    4 star(s)

    Outlier: Conclusion From my results graph, one thing is obvious: when you increase the temperature, the rate of reaction increases until you get to 40�C onwards. I found that at 0�C the average rate of reaction was 0.3cm3/s. However at 40�C, it was 1.67cm3/s, but then at 60�C it dropped to 0.9cm3/s.

  2. Marked by a teacher

    Science Coursework: Investigating Osmosis in potato tissue

    4 star(s)

    * 1 x timer - so wee know when the 5 minutes are up. * 1x scales - to weigh the potato and find out its mass. * 1 x ruler - to measure the size of the potato.

  1. Aim To determine the water potential of a potato tuber cell

    The cork borer required quite a substantial force to cut through the potato. If a method was used, which did not involve the potato being handled as much during the preparation process a minimal amount of water would be lost and so the results obtained would be nearer their actual values and perhaps more accurate.

  2. The effect of acid on the cell membrane

    Test 1 Test 2 Test 3 Acid Molarity % Abs %Trans % Abs %Trans % Abs %Trans Average % Abs Average %Trans 1.0 40.0 14.0 43.0 13.0 40.0 17.0 41.0 15.0 0.1 41.0 14.0 40.5 15.0 37.5 18.0 39.5 16.0 0.01 32.5 20.0 38.5 25.0 25.5 31.0 29.0 25.0 0.001

  1. Investigating the effect of changing the concentration of an acid on the rate of ...

    A different indicator could be used, for example universal indicator, so I can track the progress of the neutralisation, by seeing what colour it is. When it has turned green (neutral, pH 7), I will know that the reaction is over.

  2. An introduction to osmosis.

    There is usually a solution on the other side of the membrane too. Inside large animals, cells are surrounded by tissue fluid. In the soil, the roots of plants are often surrounded by a film of water. Single-celled organisms such as amoeba are also surrounded by water.

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