Table of Contents
How does sugar affect osmosis?
As the concentration of sugar solution increases, change in mass of the potato decreases. That is the rate of osmosis decreases with the decrease in concentration of water molecules. Sugar molecules in the sucrose solution are too large to go through a semi-permeable membrane so water moves out during osmosis.
What does the sugar solution in dialysis tubing for?
In this practical, dialysis tubing is used as a surrogate cell membrane for a visual demonstration of osmosis and diffusion. A solution containing large molecules (Starch) and small molecules (Glucose) is placed inside the tubing; which is then placed in a solution containing iodine.
Is sugar too large for dialysis tubing?
Sucrose would be too large to pass through the dialysis tubing, so the water in the beaker should not test positive for sugar in the end result.
What are the factors affecting osmosis?
The factors affecting the rate of osmosis include:
- Pressure.
- Temperature.
- Surface Area.
- Water Potential.
- Concentration gradient.
Why are potatoes good for osmosis?
Water will move from an area of less salt to more salt (more water to less water), and so when the potato is placed in the saltwater, all the water that is inside the potato (yes, plants have a lot of water inside of them, that’s what gives a plant it’s structure) moves out by osmosis.
Why did the dialysis bag gain weight?
Why did the dialysis bag gain weight? Since the sucrose could enter leave the bag, in order to reach equilibrium, the water had to diffuse down its concentration out of the bag, causing the bag to loose weight. This concentration gradient caused water to diffuse into the dialysis tubes making the tubes gain weight.
What is the best explanation for the color change that occurred?
What is the best explanation for the color change that occurred inside the “cell”? The iodine diffused into the “cell” and changed the starch to blue-black.
What does the water outside the tubing represent?
In the presence of saliva, the large starch molecules are broken down into smaller maltose molecules which can then pass through the visking tubing. The visking tubing represents the internal wall of the small intestine and the distilled water represents the blood.
How does osmosis affect the weight of dialysis bags?
Our job is to observe how varying concentrations of sucrose affect the weight of the dialysis bags before and after a soak, in order to track the movement of water past a membrane. Osmosis is the diffusion of water through a semi-permeable membrane. This water diffuses from areas of high concentration to areas of low concentrations.
What happens if you put glucose and starch in dialysis tubing?
If the experiment started with glucose and IKI solution inside the bag and only starch and water outside, then it will be a reverse effect. Furthermore Iodine will be released while starch & water will be absorbed. Procedure: In this experiment, a solution of glucose & starch will be placed inside a bag of dialysis tubing.
What makes glucose and iodine pass through dialysis tubing?
Glucose, starch and iodine (potassium iodide) will readily pass through the membrane of the dialysis tubing. The solution in the bag and the beaker will both turn blue-black due to the presence of iodine and starch; the presence of glucose in the bag and beaker will be investigated using Benedict test.
How to measure 30% sucrose in a dialysis bag?
Measure and pour 10 mL of the remaining 30% sucrose solution into the dialysis bag with the yellow rubber band. Seal the top of this tubing with the remaining yellow rubber band. 12.