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

Investigating the concentration of cell sap in potatoes

Extracts from this document...


Investigating the concentration of cell sap in potatoes Plan Osmosis is the movement of liquid through a semi permeable surface. The liquid passes from the dilute solution to the concentrated solution until both solutions are equal. This is needed for plants for them to get water from their roots to their stem and leaves. The cell wall of a plant cell is semi permeable. The sap inside a cell is slightly sugary. Only water molecules can pass through the membrane of the cell because they are small enough. Sugar molecules are too large to go through so they stay where they are, no matter how concentrated the solution may be. When placed in distilled water, osmosis will try and even out the concentration by absorbing in from the distilled water. This diagram explains what happens in this situation: Osmosis also works the other way round. When the cell is placed in a high concentration of sugar, the water from the sap vacuole flows out from the cell into the surrounding water until it is the same concentration. ...read more.


Variables This table shows all the variables I will be changing, keeping the same and measuring: Keeping Changing Measuring * The amount of water poured over the potato. * Starting weights * The concentration of the water. * The group weights of the potatoes * The start and end weights of the potatoes in each experiment. Prediction What I predict is that, the potato in the distilled water will gain in weight a lot. And the potato in the strongest solution will lose a lot of weight. I predict this because of what I have said in my introduction. The distilled water has a low concentration so more will be absorbed into the cell to even it out. And the potato in the high concentration will lose weight as water will be lost from inside the cell to even out the concentration. This is my predicted graph: Obtaining Results The tests were carried out as stated above and these were the results that were recorded: Concentration BEFORE AFTER BEFORE AFTER BEFORE AFTER Avg. ...read more.


My results conclude that in dilute water, the weight increases and in concentrated water, the weight of the potato decreases. Evaluating The experiment went quite well. We did have two weird weights of some potato so we did those again and got some more reliable answers. On the graph, the weights were all close to the line of best fit, except for the 0.1 molar one, we probably had some inaccurate answers or the solution we were using wasn't exactly 0.1 molar. My results did allow me to make a firm conclusion so therefore must be very reliable. To make this test error-free, then the potatoes would have to be all the same weight and all have the same surface area. Also, the concentration we use would have to be exactly correct and use only 5ml. The Petri dishes could also be held in an incubator to keep the same temperature. Another experiment to measure osmosis would be to place plants into different concentrations of sugar and water and test their leaves for any changes. This would show how far osmosis can go up the stem through different concentrations. ...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

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

    4 star(s)

    Size of the molecule: Size of the molecules comes into consideration while sorting out the rate of osmosis because the molecule has to be of a smaller size than that of the pores in the membrane. Large molecules stay in one side.

  2. Marked by a teacher

    The Effect Of Temperature On The Permeability Of The Cell Membrane

    3 star(s)

    Within the phospholipid bi-layer there are proteins and these proteins consist of polypeptide chains. As temperature increases from 40-60 degrees Celsius the average absorbance increases and the molecules vibrate so energetically that these bonds break easily and produces holes within the cell wall and phospholipid bilayer.

  1. Investigating Water Potential Of Potatoes.

    the concentration of the potatoes contents can be found from the graph drawn and this figure can be cross matched onto a graph showing water potential at various sucrose solution concentrations. METHOD APPARATUS: 1. 10 Test tubes,( to put the solution and potato in)

  2. Investigation on Osmosis using a potato.

    obtaining the wrong results, which could lead us to the wrong conclusions. First of all, and most importantly, we will have to get the measurements and the weights of the solutions and the potatoes as exact, and as accurate as possible.

  1. Osmosis In Potatoes.

    Hypothesis: I predict, that as concentration increases, the weight and length of the potato chip will decrease. My reasoning behind this, is that the higher the concentration of glucose in a solution, the lower the concentration of water. When the potato chip is put into the solution, it will, by

  2. Osmosis in potatoes.

    more it can take in but leave it in too long and it will rot so the time shouldn't be too long. o Concentrations of sucrose - if the concentration of water in the solution is high then the chip will take in more water than if it were a solution where there was a low concentration of sucrose.

  1. Discover whether the concentration gradient affects the rate of osmosis in a potato cell.

    We will not have to keep the percentage of the solution the same as this is the variable we are changing in the experiment. I also found much of this information by looking at notes from Miss Spilsbury's class, which state that the kinetic theory says the hotter the temperature the faster the rate of reaction.

  2. Osmosis in Potatoes.

    Measure each chip to 3cm using a ruler. This must be done carefully as a change in the surface area may allow more or less osmosis to occur. 4. Get the test tube and the measuring cylinder and pour in 40ml of undiluted sucrose solution.

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