Fehling’s solution to test the presence of glucose. The following figure (Figure 6) shows this experiment set up.
Figure 6: Dialysis tubing setup
2. Experiment B: Observing the osmosis process using potatoes as membrane At first, students were given with 2 raw potatoes and one boiled potato. All the potatoes were peeled off and a cavity was made in each of the potato. Then, potatoes were kept in a tray. The cavity of one raw potato and one boiled potato was filled with the same amount of salt as a solute and other raw potato was kept without any solute inside the cavity. After that, water was poured into the tray until the potatoes were half-submerged in the water. After a considerable amount of time (approximately 45 min), the set up was
Experiment A: Using dialysis tubing to understand passive movement
The result of this experiment was, distilled water with glucose was shown pink color while heating in the presence of Fehling’s solution, but distilled water with starch did not show any color change. Thus, it shows that glucose dialysis tubing was undergone through osmosis process, but not the starch. It is possible to say that it is because starch is a larger molecule than the glucose. So, it cannot cross the semi permeable membrane without the help of membrane proteins. As this was an artificial set up for membrane, there were not carrier proteins to facilitate the starch movement across the membrane.
Another finding from this experiment was the volume change of glucose solution in the dialysis tubing. When the osmosis was taking place, the water molecules from the distilled water would have entered into the dialysis tubing. At the same time, the solute was moving across its gradient and finally water and glucose molecules came to at equilibrium point, where both the molecule concentrations were evenly covered all over the distilled water solution and the dialysis tubing and it caused the volume decrease inside the tubing. Thus, our hypothesis was accepted that the glucose would be undergoing
Briefly describe an alternative technique that could be used to measure the amount of glucose within sports drinks. (5 points)
We then took 1ml of the 10% glucose solution again using the glucose rinsed pipette and added it to test tube 1, we then filled the H2O rinsed pipette with 9ml of H2O and added it to test tube one; making 10ml of 1% solution.
Method: [IMAGE] Equipment needed: Ruler Measuring Cylinder Scalpel Tongs Pipette Thermometer Tri-pod Stop-clock Gauze Delivery Tube Bunsen Burner Beaker Matches/Lighter Potato Hydrogen Peroxide Solution (20%) Water Lead Nitrate The skin of the potato was removed using a scalpel and then cut into 1cm², using a ruler to measure the size of each cube, four cubes are required for each experiment, and therefore at least 36 cubes are required for the full experiment to take place. Fill a beaker half way with water, and place a thermometer in the water. Allow the thermometer to warm to room temperature to gather an accurate reading, and measure the temperature, using the thermometer. A measuring cylinder was used to put 10ml of Hydrogen Peroxide Solution into a
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.
On a cellular level, Mrs. Jones’ cells are dehydrated due to osmotic pressure changes related to her high blood glucose. Cells dehydrate when poor cellular diffusion of glucose causes increased concentrations of glucose outside of the cell and lesser concentrations inside of the cell. Diffusion refers to the movement of particles from one gradient to another. In simple diffusion there is a stabilization of unequal of particles on either side of a permeable membrane through which the particles move freely to equalize the particles on both sides. The more complex facilitated diffusion is a passive transport of large particles from a high concentration of particles to a lower concentration of particles with the aid of a transport protein (Porth, 2011). The cellular membranes in our bodies are semipermeable allowing for smaller molecules to flow freely from the intracellular to extracellular space. The glucose molecule, however; is too large to diffuse through the cellul...
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.
...s a component monomer of starch. As a monomer as opposed to a polymer, it is much smaller and would thus be able to cross the plasma membrane. However, glucose is a larger solute than the component ions of salt, thus meaning that simple diffusion would not be sufficient. Instead, facilitated diffusion would be needed to transport the glucose. However, in the dialysis tubing, there is no facilitated transport like there is for the plasma membrane. Thus, the glucose may pass through the dialysis tubing, but it would not be due to transport, but the artificial enlargement of the passages in the dialysis tubing. Water would move freely inside and outside of the cell, however, because there is a greater solute concentration inside the cell, the water would diffuse through osmosis into the cell model, increasing the final mass of the dialysis tubing and causing cytolysis.
To investigate the osmotic effect of changing the concentration of sucrose solution; distilled water, 20% sucrose solution, 40% sucrose solution, 60% sucrose solution on the change in mass of potato cylinder after 30 minutes of being in solution.
At point A the graph shows that no change in mass, of the potato, would have have occurred had we used a 0.2 (m) sucrose solution. This suggests that the concentration of water inside the potato would have been equal to the solution outside the potato. At point B (plain water), there is no indication that the cell is increasing in mass. This is because the cell is fully turgid and no more water can enter.
Materials used in the experiment included 5-7 g of the potato tissue, 50ml of 2.0M phosphate buffer coffee filter and guaiacol dye.
In conclusion, the method seems flawed in accurately measuring the glucose concentration of solutions. To make the experiment a "fair test," three main variables needed to be kept constant. Firstly, the volumes, including all measurements, i.e., the amount of Benedict's solution used and the amount of glucose water solution in each test tube. Secondly, the time that all the test tubes were kept in the water bath had to be the same for all test tubes, including solution X.
Investigation of the Concentration and the Effect of Sucrose on Osmosis in Apple and Potato Tissues
* Size of potatoes * Diameter of each potato tube * Time in sugar solution We need to make sure in both experiments the fair test lists are used and the procedures are carried out. This needs to be done otherwise my results will not be accurate and will look odd. Method: Firstly we got out all our equipment.
the length of time I kept the potato in the solution as I only kept
Equipment Potato, Borer, Beakers, Measuring Cylinder, Stopclocks, Distilled Water, Electronic Balance, Salt solutions of various concentrations. Diagram [IMAGE] [IMAGE] [IMAGE] When we leave the potato in the solution for the allocated time, water