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Osmosis Concentration Gradient

Paper Type: Free Essay Subject: Biology
Wordcount: 2404 words Published: 7th Aug 2018

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Plant cells at all times have a tough cell wall adjoining them. When they occupy water by osmosis they begin to swell up, but the cell wall prevents them from bursting. Plant cells turn into turgid when they are placed in dilute solutions. Turgid means swollen and tough. The pressure inside the cell increases; ultimately the internal pressure of the cell is so high that no more water can enter the cell. This liquid or hydrostatic pressure works in opposition to osmosis. Turgidity is incredibly vital to plants since this is what makes the green parts of the plant keep upright. Given that potatoes are plants the similar thing will occur to its cells, they will enlarge and become extra turgid.

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But if a plant cell is put in a concentrated sugar solution it will drop water through osmosis and become flaccid, this is the precise opposite of turgid. So, if you then place the plant cell into a concentrated sugar solution and also look at it beneath a microscope you would notice that the inside of the cells have shrunk and pulled away from the cell wall, this would be known as plasmolysed.

But if a plant cell is put in a solution which has accurately the similar osmotic strength like the cells they are in a position between turgidity and flaccidity.

The water movement of a cell has the potential of disturbing a whole organism as contrasting to just a single cell. This can be achieved through numerous diverse ways. First of all, if water is occupied into a plant through the roots the ending consequence will be the hydration of the whole organism. Also, if a plant cools down, water or sweat is unconstrained and passes throughout the organism.

In this investigation I have used many scientific definitions, which I have explained below:

Hypotonic – A hypotonic cell surroundings is an atmosphere with a minor concentration of solutes than the cytoplasm of the cell. Within a hypotonic environment, osmosis creates a current of water into the cell, causing the growth and spreading out of the cell. The growth may perhaps guide to the bursting of the cell. A hypertonic result has a higher concentration when compared to the cell. Hypotonic means it has a lesser concentration compared to the cell. Isotonic is a condition in which the concentrations of the cell and of the solution are in an identical proportion.

Plasmolysis – Plasmolysis is the reduction of the protoplasm of cells inside plants suitable to the loss of water during osmosis. It is while the cell membrane takes off the cell wall and the vacuole collapses when put in a hypertonic atmosphere. The reverse of Plasmolysis in plant cells is cytolysis.

Hypertonic – A hypertonic cell atmosphere has a bigger concentration of solutes at the outer of the cell. Consequently, in hypertonic surroundings, osmosis makes water to run out of the cell. If a sufficient amount of water is taken away in this way, the cytoplasm will contain such a tiny concentration of water that the cell has trouble working.

Turgor Pressure – Turgor pressure is the risky internal pressure in a cell ensuing from osmotic pressure.


I expect that when there is a high concentration of sucrose the water molecules from inside the potato section will go away from the potato and set off into the sucrose. Since sucrose has a big concentration of sugar and a small concentration of water, this is subsequent laws of osmosis. Once the procedure has happened, the cell of the potato will happen to be flaccid. In addition, as the quantity of sucrose in the solution increases the potato piece will get smaller more and as the quantity of distilled water increases in the solution, the potato piece will become turgid.

I expect that the more water there is in the solution, the more the potato cell will swell up, which would make it turgid. This will raise the total mass of the potato however; the cells will not come apart as the cellulose cell wall is inelastic. Because of the Turgor pressure the inside of the cell will initiate to move forward alongside the cell wall and provide support to the plant tissues.


There are numerous diverse variables which may well affect the results of the experiments. They are listed below:

Mass of the potato piece: The size of the potato piece must be tiny enough to fit within the tube. The size ought to be large enough to observe an outcome in mass following the experiment. This variable will be controlled by cutting and measuring the mass on weighing scales.

Concentration of Sucrose: The concentration of the sucrose must not be excessively large, or else the molecules of the potato will travel towards it rapidly and the weight of the potato will rise too fast. It must not be excessively low or else the potato will become bigger in size as the water molecules will shift from the solution into the potato. This variable will be controlled using equal concentration of sucrose in every experiment but will be changing the amount.

Amount of Sucrose: The amount of sucrose is the variable which I will be changing. This is because by changing the volume of sucrose but keeping the quantity of the solution stable, the concentration of sucrose becomes more diluted. So, from there I preserve the result of different concentrations on osmosis.

Temperature: The temperature should stay stable to maintain the investigation to be fair. The experiments ought to be carried out in the same area with the same equipment to keep reliability of results accurate as possible. It must stay put at room temperature to guarantee fairness and reliability.

Time: Every experiment must be recorded up to a firm time. It must not be too lengthy or there would be sufficient time for the water molecules to travel in or out of the potato making incorrect results. If it is not long enough then there would not be sufficient time for osmosis to happen. The time must stay the same all the way through the experiments to make sure it is fair and to guarantee that the results are similar.

To ensure the experiment to be fair, some aspects of the experiment will have to be kept the same, at the same time as one key variable is changed. If the experiment is not a fair test, I will be getting the incorrect results which could guide me to the wrong conclusions. I have preferred to vary the concentration of the sugar solution.

The primary and mainly the important thing to do, is to get the measurements of the solutions and the mass of the potato cores as precise as possible. This will be prepared to each single potato core. I will use a ‘size 6’ cork borer to get the potato cores out of the original potato. I will be equally cutting the potato cores with a scalpel to make them as identical in length as achievable to make it a fair test. I will clarify how the length will influence the result of osmosis beneath. I will also be measuring the length to the nearest millimeter. If some of the non-variables are not kept steady, this would then not be a fair test then. If we obtain the potato core for example., if the potato core was taken away with several cork borers, then the potato core would be a different width, or else if one potato core was longer than another potato core, there would be an raise in surface area which would consequently mean that there is more surface area for osmosis to take place which would either mean that the potato core would be heavier than it should be or lighter than it ought to be.

I will use the same top-pan balance to weigh my potato cores because measurements can faintly differ between scales. Before using the scale, I will wipe the scale as it would have been used by other fellow classmates.

The potato core to be entirely covered in the sucrose solution is too another very important part in order to make the experiment as fair as achievable. Because if the potato core is not entirely covered by the sucrose solution, the outcome of osmosis will not take place to its fullest and I would obtain dissimilar readings of the mass for each potato core, which will also make the test unreasonable. For that reason, I will use 10cm of every concentration of solution for each potatoes core. Carrying out the experiments in stable temperature surroundings is extremely essential. The temperature can have an effect on the consistency of the experiment. Every test tube will be located in the same site at room temperature. On the other hand, this might not create a constant environment.

Obtaining and experimenting with the accurate measurement of concentration of sugar solution is awfully important to the experiment. If the amount of one solution in a test tube is greater or lower than another, it will influence the pattern of results. E.g. if the amount of solution is greater than the rest, it would be rather possible that there will more osmosis taking place, bearing in mind that there is additional sucrose solution, while there is a smaller amount of solution in the test tube, not as much osmosis will happen. Yet again, this cannot always be correct. I can always find out by essentially doing an experiment where I put two potato cores of the identical length in separate test tubes in the same concentration of sugar solution but with a dissimilar amount. E.g., one potato core can be placed in a test tube of 10ml of 0.50M of sugar solution and one potato core can be put in a test tube of 25ml of 0.50M of sugar solution.


Distilled Water


Sucrose Solution


Cutting plate


Test Tubes

Measuring Cylinder

Weighting Scale

Initially I will make sure that every potato piece weighs approximately the same. In addition, I have to make the surface area available the same. All of the potato pieces will be cut 4cm by 1cm by 1cm.

Once I weigh the potato pieces, I will put them into fifteen different test tubes. Then I will make the solutions of distilled water and sucrose concentration. The concentrations will vary by: 5ml in each test tube, each experiment will be repeated three times.

Each experiment will be repeated three times

Experiment No.

Sucrose Quantity (ml)

Distilled Water Quantity (ml)


I will put in the dissimilar amounts of sucrose to water into dissimilar test tubes.

I will leave the solution for 24 Hours and then take measurements.

All experiments will be repeated 3 times and an average will be prepared to enhance accuracy.


Safety glasses are not a critical part of safety, because there are not any dangerous chemicals I will be using in this experiment.

Each and every apparatus must be labeled visibly; as a result there would not be any disorder.

A first aid kit must be set aside nearby to save time in case of a cut ought to happen all through the experiment.

Preliminary Results

From my Preliminary Results, I am to trying to find out:

If the length I have chosen is a good choice

If I will change the concentrations

If the method should be changed or not


Preliminary Results-Changes to be made for Actual Experiment

If the length I have chosen is a good choice

To cut the potato piece to 4cm took a long time, the length was also too big, so therefore for the actual experiment, every potato will be 3cm by 1cm by 1cm.

If I will change the concentrations

The concentrations used are perfect and the results given are consistent.

If the method should be changed or not

The method used was well-organized and straightforward. It was enormously simple to replicate and since I have carried it out numerous times I have become used to the method, so the method will not be changed and will be the same as the Prelimary experiment.



After the finishing point of the investigation I can bring to a close, that correct results were produced. I have presented my data in two ways, graphs and the tables above. I drew graphs because you are able to spot any trends. My results evidently show the comparison between increasing the concentration of sucrose-mass of potato will decrease. My graph can be said to be a straight line, so my results are accurate and reliable. From my outcome I can see that as the concentration of sucrose increases, there is a steady increase in the percentage change of the potato mass.At highest concentration the potato has lost the most mass – 54%, this will be called flaccid. So, the concentration gradient was at its maximum, for this reason the highest rate of osmosis took place at this concentration. Still, as the sucrose concentration altered to lesser values the loss in mass from the potato also decreased. Once the concentration of sugar was completely water, the potato had gained mass 20%. Osmosis of water molecules was currently going on back into the potato. At that point the Potato Cells were Turgid. From the outcome I can say that my prediction was right. At high sucrose concentrations the potato lost mass and became flaccid, and at small sucrose concentrations the mass enlarged. This would be because of osmosis taking place, the water molecules moving from low concentration of sucrose to the high solution in the potato.


On the whole, the investigation was good. As I did a preliminary experiment, I could make changes to the Actual Experiment.

From looking at the 3 graphs and the tables, it can be said, there were no anomalous results. This can be said because the values are precise and accurate with each other.

The method used was well-organized and reliable upon. I used the same method in the preliminary and the Actual Experiment, this was good for me as I got used to the method and the whole experiment became easier for me. In the experiment, I could have improved accuracy, if I did the experiment further times. I could have also tested more Sucrose concentrations. Also, I could have measured every hour instead of 24 hours. I can also carry out an investigation into how osmosis is affected when it takes place in different conditions, i.e. Low and High temperature.


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