Lab 2 Diffusion

Certain substances are able to diffuse across plasma membranes under the right conditions through selective permeability. The selection of these certain substances allows for cells to maintain homeostasis, as these substances move from higher concentration to lower concentration. The purpose of this experiment is to see whether or not Lugol’s will be able to diffuse across dialysis tubing, which acts as a membrane. Lugol’s turns black when it interacts with starch, which will make the diffusion easy to see. This is all based off of a caterpillar eating a plant. The starch present in the leaves causes the caterpillar to produce amylase, which breaks down starch. In one experiment, the tubing will contain starch and amylase, while the other tubing

4. Does the dialysis bag or the beaker contain more starch? What about glucose? The dialysis bag does contain more of the glucose and starch than the beaker does.

If the solution in the left beaker contained both urea and albumin, which membrane(s) could you choose to selectively remove the urea from the solution in the left beaker? How would you carry out this experiment?

3. Use friction at the other end to open and then fill the dialysis tubing (your simulated cell) to approximately 75% (3/4 full) with one of the solutions indicated below using your transfer pipet, and seal the open end with another rubber band. Make sure that you have a tight seal with the rubber band as you are attempting to create a sealed system in the

The Diffusion and Osmosis Lab determines the molarities of various sucrose solutions based on change in mass. Using table sugar in different amount of molar concentration 0.0M, 0.2M, 0.4M, 0.6M, 0.8M and 1.0M. The molarity of the solution of the sucrose solution in the dialysis tubing determines the amount of water that either move into the bag or out the bag, which also means its mass changed.

This is an individual study investigating the process of diffusion, osmosis and active transport. To start you should know that substances are moving in and out of cells of your body all the time. To understand and make sense of the cells of your body, you need to know about the process of diffusion, osmosis and active transport.

Dialysis tubing is a membrane made of regenerated cellulose fibers formed into a flat tube. If two solutions containing dissolved substances of different molecular weights are separated by this membrane, some substances may readily pass through the pores of the membrane, but others may be excluded.

Introduction: Chemical reactions are dependent upon two factors: temperature and concentrations of substance. We can monitor the rate at which a chemical decomposes or the rate at which a chemical substance appears. In this experiment we will be measuring the rate of decomposition of hydrogen dioxide with the following reaction:

1. The relationship between rate of diffusion/ osmosis, volume, and surface area can be easily seen and analyzed through the data that was collected from procedure one: Surface Area and Cell Size. Phenolphthalein is a dye-material in this lab that was used to determine whether a substance was an acid or base. This could be told as the phenolphthalein changed into a murky. Muddled and clouded color when mixed with acids. When the chemical aid was mixed in with a base, the color

The hypothesis states that if the solution is hypotonic the results will decrease, if the solution is hypertonic the results will increase and if the solution is isotonic the solution will vary and or remain constant. In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Then dialysis tubing A was placed into beaker 1 with B, C, and D placed into beaker 2 for 45 minutes and weighted at 15 minute intervals. My finding in the study was that each of the four samples changed from their initial weight and for the most part accurately proved the hypothesis.

We filled bags of dialysis tubing with 20 ml of sucrose, NaCl, ovalbumin, and glucose and weighted them. After soaking them in distilled water for 10 minutes we measured them again. All of the bags gained water. Our hypothesis was that water will diffuse into the cells with ovalbumin, NaCl, glucose, and sucrose, but not the bag with distilled water. The independent variables were the different solutes in the dialysis tubing. The dependent variable was if the water would diffuse into the

Diffusion and Osmosis Experiment with a Shell-Less Egg After Three days of Testing Methods with Water and Corn Syrup

The diffusion across a cell membrane is a process of passive and spontaneous net movement of small lipophilic molecules. The molecules move from a high concentration to a low concentrated region along the concentration gradient. The result being a point of equilibrium, this is where a random molecular motion continues but there is no longer any net movement. However, there are things that can affect the rate of diffusion, these being temperature, surface area, concentration, size of the molecule, permeability, diffusion distance and concentration difference. Osmosis is a type of diffusion as it is the movement of water molecules through a semipermeable membrane into a region of higher solute concentration. Equilibrium is reached when the solute concentration is equal on both sides. Water potential is measured in kiloPascals, it is the measuring of the concentration of free water molecules that are able to diffuse compared to pure water, which is 0 kilopascals. It is a measure of the tendency of free water molecules to diffuse from one place to another. The result being, the more free water molecules, the higher the Water Potential. However, Water potential is affected by two factors: pressure and the amount of solute.

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

After reviewing the data collected, we reject the hypothesis because the weights of all the tubes changed over time. The weight of the glucose increased by 0.71 grams. The sucrose increased by 0.89 grams. The sodium chloride increased by 0.59 grams. The albumin decreased by 0.07 grams. The distilled water increased by 0.38 grams. The glucose and sucrose are carbohydrates. The large change in their weights prompts the question of whether the dialysis tubing allows more carbohydrate molecules to diffuse. The very small decrease in the albumin, a protein, suggests that the dialysis tubing does not allow many protein molecules to diffuse. Based on the fluctuation of weights it can be assumed that diffusion and osmosis both occurred, either individually or simultaneously. The semipermeable dialysis tubing aided the diffusion and osmosis. This observation leads one to question if the weight of an organism’s cells is constantly fluctuating due to diffusion and