Biology osmosis coursework potato

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Contents:
  1. Potatoes in Saltwater
  2. Osmosis In A Potato Chip Coursework
  3. Osmosis lab report

Presented below is a sample of a simple potato Osmosis lab report that you can use as a guide when writing your lab report if you want your work to be awarded reasonably high marks. Introduction - Osmosis is a unique type of diffusion whereby solvent molecules move from a region of high concentration to a region of low concentration through a selectively permeable membrane.

Methods - The first step is to peel the potato. The second step is to cut both the ends of the peeled potato. The idea here is to come up with a potato that is flat on both sides. Thirdly, you need to estimate the center of the potato and then make a cavity or a hollow that runs from one of the flat side of the potato to almost the other end of the potato. The fourth step is to mark the point that separates the Petri plate into two halves and pour distilled water up to this point.

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This is followed by marking the level of the solution in the cavity using one of the pins. The eighth step is to leave this experiment uninterrupted for three hours or so. Finally, you should mark the changes in the level of the solution in the cavity in the potato using the second pin.

This explains the rise of water in the cavity in the potato. Conclusion - The concept of osmosis is clearly demonstrated by this experiment. Water molecules are observed to have moved from the region where they are highly concentrated to the region where they have a low concentration through a semi-permeable membrane in the cells of the potato.

From the experiment, it can be deduced that in order for osmosis to take place there must be a semi-permeable membrane that separates two regions that have different concentration of solvent molecules. Osmosis can, therefore, be used to explain how plant cells get water from the soil and the transpiration process whereby plant cells lose water into the atmosphere. When water is entering a plant cell, its wall a semi-permeable membrane prevents excess water from entering as this can make it burst due to osmotic pressure. Timely Delivery. Sound Research. Recent Sources.


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Potatoes in Saltwater

Involved in this process are hypotonic, hypertonic and isotonic solutions. A hypotonic solution is onewith a lower osmotic pressure, indicating that the net movement of water moves into the saidsolution whereas a hypertonic solution is one with a higher osmotic pressure, thus the netmovement of water will be leaving the hypertonic solution. Lastly, an isotonic solution entails no netmovement of water across a semi-permeable membrane as the two substances involved displayosmotic equilibrium. Thus, we can state that there appears to be a negative correlationbetween NaCl concentration and the mass and length of the potato strips, clearly evident in theabove graph which shows an exponential decrease in both mass and length.

This occurrence can be explained through the process of osmosis. As mentioned in theintroduction, a hypertonic solution is one with higher osmotic pressure meaning that the netmovement of water leaves the solution. Since the solution it is submerged in is higher inconcentration in water molecules, or hypertonic, the water molecules will diffuse into the area oflower H2O-concentration the potato strip in order to achieve equilibrium.

Osmosis In A Potato Chip Coursework

Alternatively, thedecrease in mass and length in the potato strips submerged in highly concentrated NaCl solutionscan be explained by its immersion in a hypotonic solution. Hypertonic solutions, as mentioned.


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  8. Potato OsmosisBiology SL - AThbefore, are described as those with lower osmotic pressure, indicating that the net movement ofwater moves into the solution. Therefore, as NaCl solution is less concentrated in H2O moleculesthan the potato strips, the decrease in mass and length and loss of turgidity results from the netmovement of water leaving the potato strips, which is higher in osmotic pressure, and diffusing intothe solution.

    Nevertheless, there are several possible sources of error that could have greatly ornegligibly affected the outcome of the experiment. First, we must note the varying external factorsresulting from an uncontrolled environment — the biology classroom. Primarily, these would includevarying temperatures and humidity which could potentially affect the rate of osmosis as increasedtemperature results in increased diffusion while increased humidity results in an increased numberof water molecules.

    Secondly, we must note the human errors involved, for example, miscalculationsin experimental preparations. This leads us to the errors resulting from variances in the substances used.

    This stems fromthe differences in water content of each potato, as, for example, a potato with high waterconcentration in highly concentrated NaCl solution would have a faster rate of erosion. Furtheraffecting factors could include barriers to diffusion such as the size of pores which would alsodetermine the rate of osmosis. All the mentioned errors above hold the possibility of skewing thedata.

    Osmosis lab report

    Subsequently, such errors could have an effect on the reliability of the results. The level ofaccuracy which has been used throughout this investigation would come into question as acombination of these errors would not permit such precision.

    Biology PAG 8: Osmosis in potato

    Values of percentage change havebeen taken at two decimal places corresponding with the actual values of mass and length, however,this could be seen as far too precise. A better option would have been to take percentage change aswhole numbers or at one decimal place. Nevertheless, we attempted to reduce the potential errorsthrough several measures. With surface area, a cork borer was used in order to uniform the size ofthe potato strips while the varying concentration gradients were controlled through the completionof several trials three trials with three potatoes in order to limit error.

    Furthermore, to control theeffects of the external environment, foil was secured over the beaker containing the submergedpotato strips.

    However, if we refer to the graph, we can see the minimum and maximum spread foreach data-point is generally close-set while the R2 value, which calculates the spread of the data-points from the line of best fit, are both relatively high — both around 0. This demonstrable trendindicates a limiting of the amount of error, and thus fairly reliable results despite possible errors.