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

The aim of this experiment is to work out if potatoes lose or gain mass in different sugar solutions due to osmosis and to solve where the water concentration outside the cell is equal to the concentration inside the cell;

Extracts from this document...


The Aim: The aim of this experiment is to work out if potatoes lose or gain mass in different sugar solutions due to osmosis and to solve where the water concentration outside the cell is equal to the concentration inside the cell; this is known as the isotonic point. In the investigation I would have to be as precise and accurate as I possibly can in order to have a reliable set of results for a good conclusion. Introduction: I am going to perform an investigation on osmosis in potato cells. Osmosis is the movement of water molecules through a semi permeable membrane, separating solutions of different concentrations. The water molecules pass from a region of high concentration to a region of low concentration. 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. Many cell membranes behave as semi permeable membranes, and osmosis is a vital mechanism in the transport of fluids in living organisms, for example, in the transport of water from the soil to the roots in plants. If a cell is in contact with a solution of lower water concentration than its own contents, then water leaves the cell by osmosis, through the cell membrane. ...read more.


Fig. 1 Volume of distilled water (cm3) Volume of 1Molar sugar solution (cm3) Concentration of sugar solution (M) 10 0 0.0 6 4 0.4 2 8 0.8 0 10 1.0 I chose these certain concentrations because I wanted there to be a distance between the concentrations in order to get a wider set of results and a smother curve on my graph. If I chose concentrations that were close together I would not be able to see much difference between the concentrations and it would affect the graph because it would not be clear to see changes between concentrations. So in other words doing so makes my results more reliable because of the wide range. Precautions: During this investigation the measurements for the solutions had to be precise as to not change the outcome of the experiment. I had to ensure that I took care cutting the potatoes because I could have easily cut myself by accident. I also had to ensure that every time I handled the potatoes my hands were clean and dry. This was to stop any kind of contamination and made sure that I did not pass on any extra water onto the potato which would alter the tables of results for all concentrations. How I kept it a fair test? : To create a fair test certain aspects of the experiment will have to be kept the same whilst one key variable is changed. ...read more.


So I believe that the reliability of my investigation is sufficient to back up my conclusion. I have several proposals for further experiments to provide additional evidence for my conclusion. I would like to undertake another experiment with sucrose concentrations at 0.05 intervals from 0 to 1. I would like to do this as I feel it would provide a better and more reliable set of results and a more justified conclusion. When there are more concentrations the shape of the curve shape can be seen more clearly, I suspect that at the lower concentrations of sucrose the graph falls more steeply, flattening off at higher concentrations. I would also like to conduct an investigation, in conjunction with this experiment, to calculate the concentration of sap within the vacuole. To do this, I would find between which parameters the curve crosses the x-axis of sucrose concentration and retest at every 1% between these two parameters until I have found the concentration which contains a core that neither gains nor loses mass. This osmotic concentration would be the equivalent of the sap in the vacuole (isotonic point). As an extension to this investigation, I would run two experiments in parallel. All cores would be from the same potato, but one would run for an hour, as this one did and for the other the cores would be left in the solutions for longer, perhaps 24 hours, to establish if one hour is the end point of the osmotic diffusion. ...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 Potatoes Lab. At which concentration of sucrose in water (% mass ...

    5 star(s)

    in mass of each potato core at each time using the formula: [(final mass- initial mass)/ initial mass] x 100 = % Change in Mass 0% Mass by Sucrose in Solution o At .5 Hours: [(1.619g- 1.506)/ 1.506] x 100= 7.5% o At 24 Hours: [(1.553g- 1.506)/ 1.506] x 100=

  2. Experiment investigating concentration of sucrose solution and potatoes

    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.

  1. In this investigation the main aim is to find out how many grams of ...

    The point that the line of best fit passes through the X axis of the graph is where the isotonic point is found in this investigation on both graphs the isotonic point is 0.5g of salt per 100ml of water.

  2. Free essay

    Aim and background knowledge: - To investigate how different concentrations ...

    3.67 4.15 3.82 3.78 3.80 Mass After (g) 4.26 4.34 3.66 3.16 3.22 Change in mass (g) 0.59 0.19 -0.16 -0.62 -0.58 Percentage change in mass (%) 16.08 4.58 -4.19 -16.40 -15.26 Explain the conclusion using biological knowledge and ideas: When the potato chip is placed into the test tube, osmosis starts to take place.

  1. What is the concentration of sugar in potato cell?

    The solutions will be clearer than the more dilute ones. This prediction is based on the fact that the potato concentrations are lower than the solution, so water molecules will move to the solution from the potato which will lose mass and its cells will lose their shape and size

  2. Osmosis, What is the effect of sucrose concentration on the rate of osmosis in ...

    This indicates that the concentration within the potato cell is closer to 0.0M than 1.0M. To expand on this idea, I drew a graph of my results and connected the two average points together. The isotonic point, where the line crosses the x-axis, shows the concentration inside the potato cell.

  1. Osmosis. To investigate which sucrose concentration is the same as the concentration of cell ...

    it swell up due to the fact that its vacuoles are now full of water. On the other hand, if the potato is placed in a strong sugar solution the opposite will happen - the water will move out of the potato across a huge concentration gradient (because although there

  2. Structures and functions in living organisms. Revision Notes

    The loop leads into a second coiled tubule known as the distal convoluted tubule. This leads into the collecting duct. 2.72 Describe ultrafiltration in the Bowman?s capsule and the composition of the glomerular filtrate Ultrafiltration is filtration on a molecular level.

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