Investigating the Concentration of Sucrose in Cells of Carrots and Potatoes
Plan
Introduction
Osmosis is defined as 'the net movement of water molecules from a
region of high water concentration to a region of lower water
concentration through a partially permeable membrane'. In my
experiment the process of osmosis will be due to the concentration of
sucrose inside the cell compared to outside. Therefore if there is a
higher concentration of sucrose molecules outside the cell then the
net movement of water molecules will be out of the cell and similarly
if there is a higher concentration of sucrose molecules inside the
cell then the net movement of water molecules will be into the cell.
This movement of water molecules causes the cells to become either
turgid, which is when the cells are filled with water, or flaccid,
which is when the cells are 'limp' with little water.
Aim
To find the concentration of sucrose in cells of carrot and potato.
Osmosis
When a substance such as sugar dissolves in water, the sugar molecules
attract some of the water molecules and they stick to the sugar
molecules. This means that there are fewer free water molecules in the
solution. When two different sugar solutions come into contact with
each other through a partially permeable membrane the free molecules
can go through the membrane easily but the sugar molecules are too
big. If one of the solutions has more free molecules than the other
then more of those free molecules will pass through the membrane than
the other way round, hence the definition. The following diagram
illustrates this
Low Water High Water
Concentration Concentration
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I also predict that solution concentration 0.3 will be isotonic because of the pressure potential. As the water moves into the cell it pushes up against the cell wall this is called the pressure potential and it increases the water potential until an equilibrium is reached, and because the cell is so inelastic it takes very little water to achieve this. That's why I believe in-between 0.3 and 0.4 will be isotonic as it is very close to pure water. Background Information Osmosis - The net movement of water molecules from a region of high water potential to a low water potential, through a selectively
The Effect of Solute Concentration on the Rate of Osmosis Aim: To test and observe how the concentration gradient between a potato and water & sugar solution will affect the rate of osmosis. Introduction: Osmosis is defined as, diffusion, or net movement, of free water molecules from high to low concentration through a semi-permeable membrane. When a substance, such as sugar (which we will be using in the experiment we are about to analyse), dissolves in water, it attracts free water molecules to itself, and in doing so, stops them from moving freely. The effect of this, is that the concentration of (free) water molecules in that environment goes down. There are less free water molecules, and therefore less water molecules to pass across a semi-permeable membrane, through which sugar molecules and other molecules attached to them are too big to diffuse across with ease.
Osmosis Experiment Planning Aim: The main subject that I will be planning to investigate is the effects of a concentrated sucrose solution on potato cells on the basis of the Osmosis theory. Background knowledge: The plant cell and its structure To understand osmosis in detail I will need to explain the plant cell (which is the cell included in the osmosis experiment) and its cell membrane. Below I have a diagram of a plant cell: [IMAGE] Osmosis is about the movement of particles from a higher concentrated solution to a lower concentrated solution to create an ethical balance via a partially or semi permeable cell membrane. Osmosis in simple terms is the exchange of particles between the cytoplasm inside the cell and the solution outside the cell. What makes this exhange is the partially permable cell membrane.
Investigate the Osmosis of Potato Cells in Various Salt Solutions. Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. I will be able to change the input of my experiment. The input variable is the concentration of the solution.
cork borer and a ruler. I will keep the potato chips the same size in
If the concentration of sucrose increases, then the mass of the potato will decrease. However, if the concentration of the solution in the beaker is less than that of the potato (such as distilled water), then the mass of the potato will increase. So, as the concentration of sucrose increases the rate of osmosis increases.
This is because the water molecules passed from a high concentration in the water, to a low concentration, in the piece of potato. Therefore, the potato in higher water concentrations will have a larger mass than in higher sucrose concentrations. i.e. The potato pieces are shown to have water potential. The attached graph shows the concentration of the sucrose solution plotted against the average mean change in mass.
So what is happening is water is moving from a high concentration, i.e. a dilute solution to a more concentrated solution. Preliminary Work on Osmosis I am going to test carrots in a small osmosis experiment to see how the experiment works with carrots and salt solution and water. Variables 1) Temperature - Keep the same 2) Number of days left soaking - Keep the same 3) Size of beaker - Keep the same 4) Size of carrots - Keep the same 5) Concentration of salt solution -
the gain or loss of water when samples of the tissue are placed in a
repeat the process 3 times in total to ensure a fair test. At the end
Investigation of the Concentration and the Effect of Sucrose on Osmosis in Apple and Potato Tissues
== = This experiment is based on the concept of Osmosis. Osmosis is the diffusion of water molecules from a region of high water concentration to a low water concentration through a semi permeable membrane (in this case, the cell potato cell membrane). The cell walls of the potato cells are semi permeable meaning that water molecules (which are small) can fit through but other bigger molecules such as glucose cannot pass through. The water molecules can flow both ways through the membrane, letting molecules both in and out.
Osmosis in Potato Tubes Osmosis: Osmosis is the movement of water molecules through a semi-permeable membrane from a high concentration to a low concentration. Diagram: [IMAGE] [IMAGE] Aim: To see the effects of different concentration of sugar solution on Osmosis in potato tubes. Key factor: In the investigation we change the sugar solution from: 0%-10%-20%-30%-40%-50% this is the independent variable; the dependant variable is the change in mass. Prediction: I predict that all the potato tubes in pure water or low concentration sugar solution will swell because water enters their cells by osmosis.
How the Concentration of the Substrate Affects the Reaction in the Catalase Inside Potato Cells
I blended on high to make the potatoes more liquid-like. I grabbed the cheesecloth and placed on the top of the blender. I poured the potato extract on the container and labeled it. I found out that I have to make 1% sugar solution so I grabbed the sugar and measured into 5 grams on the scale. I added 5 grams of sugar on 250 ml graduated cylinder and poured the water into the cylinder. I mixed the sugar with water and poured it into the saucepan. I refilled the water into the graduated cylinder and poured into the saucepan. I turned on the heat of the stove and saw the sugar dissolved. I poured into a container and labeled 1% sugar solution. I repeated the same thing with 1% salt solution by using 1 gram of salt and filled the water into graduated cylinder by 100 ml. I answered question three. In the first experiment, I grabbed four transfer pipets and used it to put solutions into the test tubes by 3ml. I labeled it and placed into the plastic cups so it can stand upright. I grabbed each test tube and poured 2 ml of catalase solution into it. I also tapped and swirled to measure the bubbles by using the ruler. I wrote the numbers into the lab report. In the second experiment, I labeled the room