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

Investigating Osmosis in Potato Cells

Extracts from this document...


Investigating Osmosis in Potato Cells Introduction Osmosis is a process where water molecules move from a high concentration of water to a low concentration through a partially permeable membrane. Potatoes are vegetables that are mainly made up of carbohydrates. They are therefore a good source of sugars. These sugars are used to supply the potato plant with energy to grow. Potatoes store starch. Because they are used for storage below ground, they do not contain chlorophyll within their cells; this is very unusual in plant cells. Aim To see the effect of salt solutions of different concentrations on the length of the potato chip and from those results, deduce the concentration of cytoplasm and cell sap within the potato cells. Variables * The possible variables within this experiment are: * Length of chip * Solution strength (% concentration) * Volume of salt solution * Type of potato (for example: King Edward) * Diameter/width of chip * Age of potato * Temperature of solution * Water purity * Time left soaking in salt solution * Type of salt The independent variable (variable that I will purposely change) in this experiment is the concentration of the salt in the solution that the potato chips are soaked in. ...read more.


* Cork borer * Knife * Accurate ruler * Accurate scales * Measuring tube * Tweezers * Cling film Safety I will conduct this experiment safely by: * Being careful while handling knives and similarly sharp objects. * Moving carefully around the lab to avoid accidents/collisions. * Handling all glassware with care to avoid breakage and injury. Prediction For the potato chip left in water (0% salt concentrated solution), I predict that water will move by osmosis, from the high concentration of water (in this case, the solution) To a low concentration of water (the potato cells). The water will transfer into the vacuole and cell sap of the potato cells, this will exert pressure on the cell walls and the potato cells will become turgid. Because each potato cell becomes turgid, the potato chip will extend in length. Because of the cell-expansion, the potato chip will become stiff. The potato chip in the solution of 10% salt concentration will decrease in length. This is because the high amount of salt in the solution means that there is more water in the potato cells than in the solution. This will result in water molecules travelling by osmosis from the high water concentration in the potato cells, to the lower water concentration in the salt solution. ...read more.


6, 8 and 10% salt concentrated solution These solutions had similar effects on the potato chips. Because there was a small concentration of water in the solution, the concentration of water in the potato cells was greater. This meant that water travelled by osmosis, from the potato cells, into the solution: which caused the potato cells to plasmolyse and the length of the potato chip then decreased. The potato chip became flaccid, or floppy. The length of the potato chip in the 6% solution decreased by 1.5mm, the length of the potato chip in the 8% solution decreased by 2.5mm, the length of the potato chip in the 10% solution decreased by 3.5mm. Evaluation Although the results I gained from the experiment were as expected and correspond correctly with my scientific knowledge, the accuracy of the experiment could have been improved. I could have done this by: * Repeating the experiment more than twice. * Using a wider range of salt concentration solutions (for example, instead of using 0-10% at 2% intervals, I could have done it at 0.5% intervals: 0%, 0.5%, 1%, 1.5% etc) Despite being unable to do this, I think that my results are both accurate and reliable. Osmosis SC1 ...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
  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work