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

An investigation into the osmotic properties of a kumara (sweet potato)

Extracts from this document...

Introduction

An investigation into the osmotic properties of a kumara (sweet potato) Aim The aim of my experiment is to find the water potential of the kumara or sweet potato by investigating the osmotic properties and hence come to a conclusion of the exact water potential. 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. Semi-permeable membranes are very thin layers of material (cell membranes are semi-permeable) which allow some things to pass through them but prevent other things from passing through. These things pass through tiny pores in the semi-permeable membrane. Cell membranes will allow small molecules like oxygen, water, carbon dioxide, ammonia, glucose, amino-acids, etc. to pass through. Cell membranes will not allow larger molecules like sucrose, starch, protein, etc. to pass through. Cells walls found in plant cells are fully permeable. A region of high concentration of water is either a very dilute solution of something like sucrose or pure water. A region of low concentration of water is a concentrated solution of something like sucrose. ...read more.

Middle

If you put plant cells into concentrated sugar solutions and look at them under a microscope you would see that the contents of the cells have shrunk and pulled away from the cell wall: they are said to be plasmolysed. When plant cells are placed in a solution which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. We call this incipient plasmolysis. "Incipient" means "about to be". When I forget to water the potted plants in my study you will see their leaves droop. Although their cells are not plasmolsysed, they are not turgid and so they do not hold the leaves up into the sunlight. Apparatus: * McCartney bottles * Stopwatch * Scalpel * Cork borer * Sucrose solution 2Molar concentration * Kumara (sweet potato) * Filter paper * Weighing scales * Syringe Variables The variables in this experiment are: size, temperature, volume of solution, surface area of kumara, concentration, maturity of kumara and pressure. The variable I will change is the concentration of the sucrose solution. Results Before (g) ...read more.

Conclusion

I cannot see an anomaly, this is most probably as the experiment was comprised of 3 sub experiments giving a fair and accurate average. An anomaly could also have been the result of the Kumara being changed at that point so the molar of sucrose in the new Kumara could have been different. The results give enough evidence to let me conclude that the Kumara gains weight in low molar sucrose solution because I know that that the kumara has a high sugar content and that using osmosis the water in the sucrose solution will diffuse from an area of high concentration to an area of low concentration. To improve the experiment I could try to do the whole experiment with the same kumara and weigh them more accurately. To further the investigation I could use potatoes or another fruit and compare those results to that of the Kumara and in doing so find out which has the highest sugar content and water potential. ?? ?? ?? ?? William Biggs Biology coursework Investigating the osmotic properties off a kumara ...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

    Investigate the water potential of celeriac.

    5 star(s)

    -12.1% -9.1% -16.6% -21.6% 1.0 Before 0.39 0.32 0.32 0.31 0.44 0.29 0.37 0.21 After 0.34 0.25 0.34 0.31 0.40 0.25 0.29 0.16 Change -0.05 -0.07 +0.02 0.0 -0.04 -0.04 -0.08 -0.05 Percentage change -12.8% -21.9% 6.3% 0.0% -9.1% -13.8% -21.6% -23.8% Using the raw data I recorded from my experiments, I calculated the change in mass.

  2. Marked by a teacher

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

    4 star(s)

    Therefore, the surface area of all the potato strips should be the same for our comparisons of the rate of osmosis to be accurate. If all the strips do not have the same surface area, some will get more access to the solution, while some strips will get less access.

  1. Marked by a teacher

    Determining the Water Potential of Sweet Potato Tissue

    4 star(s)

    of the solution will be a negative value. The higher the molarity of a solution the more negative the ? of that solution. For a plant cell the ? is a combination of solute potential and pressure potential which can be expressed by: ? = ?p ? ?s This is an ideal situation, which all cells want to achieve via osmosis by becoming turgid or flaccid.

  2. Marked by a teacher

    Effect of temperature on membranes

    3 star(s)

    Sea beet was first domesticated in the eastern Mediterranean and Middle East - although it was only the leaves that were eaten at that time. The beetroot is known for many health benefits and has been used in traditional

  1. Peer reviewed

    The comparison of antibacterial properties of herbal products and standard antibiotics

    5 star(s)

    Variables and controlling the variables: To ensure the results are accurate much attention should be paid to producing a fair test by controlling the variables. The independent variable throughout this experiment is the product being used, so either penicillin, streptomycin, tea-tree oil or peppermint oil.

  2. Investigating Water Potential Of Potatoes.

    It can also be removed by evaporation. If the cells in the stem and leaves of a plant lose more water by evaporation than they can absorb, turgor is reduced and the plant visibly droops. This is called wilting. It can often be observed on hot dry days.

  1. Osmosis in Potato cells

    0.00 Wendy 5% Sucrose 4.18 4.22 0.04 0.96 55.00 54.00 1.00 1.82 Wendy 10% Sucrose 4.44 4.36 -0.08 -1.80 55.00 53.00 2.00 3.64 Wendy 15% Sucrose 4.59 4.41 -0.18 -3.92 55.00 54.00 1.00 1.82 Wendy 20% Sucrose 4.68 4.18 -0.50 -10.68 55.00 54.00 1.00 1.82 I noticed that the chips

  2. To find out the factors affecting the refractive index of liquid by using different ...

    Height (h) (cm) Refractive index (�) (5 s.f.) 30 8.6 2.5 7.6 27.8 30.5 1.3207 40 8.6 2.5 7.6 27.8 30.5 1.3207 50 8.6 2.5 7.6 27.8 30.5 1.3207 This result is very close to the standard refractive index of pure water, which is 1.3333.

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