Diffusion Lab

Stacy Hernandez
Period 1
Mrs. Riley
AP Biology
Osmosis and Diffusion Lab I. Introduction:
Diffusion is vital to many life functions of a cell, it allow the transportation of vitally important nutrients and compounds without the expenditure of excess metabolic energy. To explain diffusion, it is as if a bottle of perfume is opened at one end of the room, then in a short amount of time a person at the other end of the room can detect the scent of the perfume; this is the process of diffusion. Diffusion is a movement from a higher concentration to a lower concentration.
A special kind of diffusion is known as osmosis, osmosis is fundamental in many industrial processes such a water purification, desalination, and waste material treatment.
M, 0.4 M, 0.6 M, 0.8 M, and 1.0 M. Then we obtained six pieces of dialysis tubing from the beaker of water and tied a knot in one end of the tubing. Afteer, we opened one piece of dialysis and poured 25 ml of distilled water into the tubing and then tied of the other end securely leaving room for expansion. Then blotted the tube dry and placed it in the cup labeled “water”. Then we repeated the same process witht eh remaining five pieces of dialysis tubing, adding a different sucrose solution to each bag: 0.2 M, 0.4 M, 0.6 M, 0.8 M, and 1.0 M. After, we then weighed each bag and recored each bag’s initial mass in Table 2. Then filled the six plastic cups approximately ¾ full of distilled water and immersed one bag in each of the the properly labeled cups. After waiting 30 minutes, we removed the bags from the cups, dried them and weighed each bag once again recording the final mass of each bag in Table 2. Finally we calculated the c=percent change in mass for each of the dialysis bags using the formula: % Change = (Final mass- Initial mass)/ Initial mass x 100 and recorded this data in table 2; also gathering the class average results of the
-just water
Osmosis
-molecules go through a semipermeable membrane.
-just water
Diffusion
-molecules spread out over a large area.
-Everything but water.
Diffusion
-molecules spread out over a large area.
-Everything but water.
-Molecules mover around to create equilibrium.
-Molecules mover around to create equilibrium.

2. Part A of the experiment was a demonstration of diffusion. Give an example of diffusion occurring in the setup. Do you think osmosis occurred in this part of the experiment? If you answered yes, explain why you believe this to be.
There is a diffusion of glucose out into the medium. No, I don’t think osmosis occurred in this part of the experiment. 3. Did the dialysis tubing serve as a selectively permeable membrane? Explain your answer.
Yes, because it restricted certain molecules or particles to diffuse through its microscopic holes. Based on the tiny size of the holes, water and glucose were small enough to fit through them, whereas starch and potassium iodide weren’t able to diffuse through. 4. In part B, what caused the mass of the dialysis bags to change? Was there more or less water in the dialysis bags at the conclusion of the experiment?