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

Investigation to find the strength of potato cytoplasm

Extracts from this document...

Introduction

Investigation: To find the strength of potato cytoplasm Plan We have chosen to investigate how the mass of the potatoes change in different sucrose solution concentrations. Introduction Osmosis is the movement of water molecules from an area of low concentration (lots of water) to an area of high concentration (little water) through a semi permeable membrane. A semi permeable membrane is a membrane that only lets selected molecules to pass through it. In a plant water is taken into the roots by the process of Osmosis. This is because the cells inside the roots have a higher concentration than the soil outside the roots. So the water from the soil moves into the cells by osmosis. When a large volume of water enters the cell, it swells causing the membrane to push against the cell wall. We say that the cell is fully turgid. When the water moves out of the cell, the membrane shrinks away from the cell wall and becomes a flaccid cell. This causes the plant to wilt, as the cells can no longer provide support for the leaves. Apparatus > Weighing scales (g) > 18 x Potato pieces (length 4cm) > 7 x Boiling tubes > 18 x Sucrose solutions at varying concentrations > Thermometer (?C) > Stopwatch Diagram Variables Possible variables: > Size of surface area of potato pieces > Temperature of solution > Different types of potatoes (assuming that the genetic make up and therefore partially permeable membranes will be more similar in the make up) ...read more.

Middle

At this point, the net exchange of water is zero and the system is in equilibrium. www.bbc.co.uk Method 1. Collect equipment 2. Set out test tubes with relevant solutions 3. Use the cork borer and measure out 4cm length of the cylindrical pieces of potato 4. Record the mass of the pieces 5. Place in test tubes with solution, at exactly the same time 6. Start stop watch 7. After 10 minutes drain out the liquid from the test tubes 8. Dry excess water off the potato pieces 9. Record the masses 10. Fill in table 11. Repeat steps 2 -> 9 x 3 12. Work out averages 13. Plot your results on a graph. Fair Test > Keep volumes the same > Keep temperature constant > Use new potato pieces each time > Check reliability of equipment > Dry potatoes - remove excess water > Same apparatus > Keep the mass of the potato pieces similar Preliminary Experiment > Place in solutions of 0.1 M, 0.4 M and 0.5 M > Immersed in solution > Left for 10 mins > 2.5cm length Results Concentration (M) Mass before (g) Mass after (g) Change in mass (g) 0.1 0.62 0.7 + 0.08 0.4 0.63 0.74 + 0.11 0.5 0.61 0.70 + 0.09 We realised it wouldn't be a vast change in mass but it is barely noticeable. ...read more.

Conclusion

However, if I was to repeat the experiment I might well increase the time of the result to allow more osmosis to happen and possibly find out the saturation point of the potato slices. The range of concentrations was adequate but I would possibly create more concentrations if I repeated it so I would have more varied results i.e. 0.05 M, 0.15M, 0.25M and so on, including the solutions we used originally. The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by length, it could well have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I would possible have found a machine to cut the potatoes as it would ensure that all the potatoes would be identical - same weight and dimensions. I could also weigh each piece on a more accurate scale e.g. 0.0000g or more. There were not many anomalous results but some were not as close to the line as others. This may have been caused by human error. When the potato pieces were removed from the tubes and dried, we may well have dried some potatoes more thoroughly than others and therefore some would have more excess water that would add to the mass. I could find another way to dry the potatoes that would ensure that all were dried equally in future. However, I am pleased with the outcome of the investigation and I think it was reasonably successful. ...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. Estimate the concentration of the cytoplasm of potato cells.

    We then placed the chips in one at a time for 15 minutes; we hoped that this would be enough time for the potato cells to reach osmotic equilibrium with the salt solution. Afterward we removed the chips from the solutions and measured the potato chips length and below are our results.

  2. Osmosis Investigation

    To find the percentage difference in length, we must use the following formula: Therefore, using the data compiled from my experiment, I will be able to find out the percentage difference in length of the tubors placed in solutions of different concentrations.

  1. Investigating the strength of cytoplasm.

    Method: First I got all the equipment that I needed out and my solutions. I next started to get the strips of potato. I will measure and cut the strips of potato, so all of the strips are 6cm. I next got my solutions, which are in beakers and measured out 40ml of each solution with a measuring cylinder.

  2. My aim is to find the strength of sucrose inside the cytoplasm of potato ...

    whilst a solution will always have more, therefore osmosis will not stop until either the semi permeable membrane bursts (under pressure from so much water going into one side of the membrane), or until the inward pressure of the membrane from being stretched, is equal to the osmotic pressure (osmotic

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