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

Plan and carry out an experiment to investigate Osmosis in Potato tissue

Extracts from this document...

Introduction

Plan and carry out an experiment to investigate Osmosis in Potato tissue Planning Aim: To investigate osmosis in Potato tissue and find its water potential, using eight different molarities of sucrose Hypothesis Osmosis is defined as the net movement of water or any other solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other. Apparatus Test tube Label Sucrose solution Potato tissue 8 x test tubes 8 x potato chips 8 different sucrose solutions labels top pan balance test tube rack Method In each test tube, put 30cm� of each solution of sucrose, and label it with the molarity of the sucrose that is in that tube, this is needed because otherwise you would not be able to plot the graph at the end showing how the molarity of the sucrose directly effects osmosis, or if the different molarities become mixed, anomalies will appear in your results. ...read more.

Middle

% change for 1st set of data % change for 2nd set of data average % change 0 6 9.3 7.7 0.0625 5 8.4 6.7 0.125 3 3.5 3.3 0.25 0 0.9 0.5 0.5 -12 -9.1 -10.6 0.75 -17 -12.9 -15 1 -21 -19 -20 1.25 -22 -15.9 -19 Analysing and considering evidence The graph shows the line of best fit for the average percentage change in mass of the potato chip over two experiments, each being forty five minutes in length. The graph is a curve that slopes downwards and does not go through the origin. Because the line is not straight and does not pass through the origin, it means that the percentage gain and loss in mass and concentration are not directly proportional. However, there is a pattern on my graph, and this is, as the concentration of the solution increases, the percentage change in mass decreases. Although the last solution being 1.25 molar sucrose, has a higher average than that of the 1 molar sucrose solution. This suggests an anomaly in my results, that either the other chips were not blot-dried to the same extent or that there was water on the chip and that it contaminated the sucrose and diluted the solution making it weaker, or that the chip cell has completely plasmolysed and that there can be no more water loss. ...read more.

Conclusion

The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by mass, it could well have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I would have possibly found a machine to cut the potato as it would ensure that all potatoes would be the same weight and dimensions. As well as the potato I could have found a more accurate way to measure out the solutions and to determine the molar concentrations. Perhaps I could have used a burette. This would ensure that I have an accurate amount of fluid in each test tube. I could also weigh each chip on a more accurate scale, e.g. not to 0.00g but to 0.0000g There were not any out of the ordinary results, but some were not as close to the line as others. This is possible a human error. When the potato chips were removed from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the mass. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same time. However with all this said I think that the experiment was truly successful and I was very pleased with the complete comparison of my results with my initial prediction Simon Herbert 8001 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction 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 AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Determining the Water Potential of Sweet Potato Tissue

    4 star(s)

    of the internal solution is equal to the ? of the external solution. Plant cells unlike animal cells do not haemolyse they become plasmolysed, I can therefore easily measure the change in mass and length without weight change being a factor because it will be the percentage weight change which will be comapred To test this I will use 1M sucrose solution.

  2. Marked by a teacher

    Osmosis. Aim: To find the molarity of potato tubers cell sap. BIOLOGICAL ...

    4 star(s)

    * I will make sure that I do not spill anything on the floor. Precautions * I will choose fresh potatoes to get accurate results. * I will make sure that all potato pieces are submerged in the solution. * I will clean the Petri dishes to get rid of the dust.

  1. Peer reviewed

    The comparison of antibacterial properties of herbal products and standard antibiotics

    5 star(s)

    As stated on page 11 in the further data section, E.coli is gram negative bacteria and by looking at the results table it can be established that the results for penicillin against E.coli are a lot lower than the results for penicillin against M.luteus.

  2. beetroot experiment

    Reaction Vessels- Other reactants with the beetroot, e.g. Distilled water ? Time- how long you are going to react the beetroot for, ask the questions: "Why that given time is chosen and relevant. ? Range- what range of readings you are going to take, it should be sufficient for reliable support.

  1. Investigating osmosis on swede cells.

    If this anomalous result was not considered then the average of the two results would be 7.45%, decreasing the average nearly by half and if this result was potted it would not fluctuate and a slope would be formed. The result for 1.0M is also abnormally high and although it

  2. Investigation on Osmosis using a potato.

    Another flaw is that we did not find any way in that which we could find that osmosis or plasmolysis could not occur any more then it is able to. To tackle the above problems in the final experiment we shall do the following.

  1. The Effect of Sucrose Concentration on Osmosis.

    But becomes more dangerous when there is a experiment going on, chemicals are in the air and can get into the food or drink. This applies for fingers as well. Nothing should be put into ones mouth during an experiment.

  2. Design an experiment to investigate the effect of temperature on the movement of a ...

    As the temperature increases the hydrogen bonds break, this causes the proteins to change shape, so they denature. This means that the pigment should be able to fit through the proteins, whereas normally it cannot. Below is a diagram of an alpha-helix secondary structure (Source- http://academic.brooklyn.cuny.edu/biology/bio4fv/page/alphab.gif)

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