Dialysis is a passive process that favors the transport of small molecules across a semipermeable membrane.

Discussion. The dialysis tubing is a semipermeable membrane. Water molecules can pass through the membrane. The salt ions can not pass through the membrane.

Osmosis and dialysis are passive processes, not needing cellular energy, because they move with their concentration gradient. Dialysis is a passive process where solutes selectively move across a semi-permeable membrane. Only molecules small enough to pass through the membrane pores will diffuse through.

What is Dialysis Tubing? Dialysis tubing is a semi-permeable membrane, usually made of cellulose acetate. It is used in dialysis, a process which involves the removal of very small molecular weight solutes from a solution, along with equilibrating the solution in a new buffer.

Serpent Skin tubing

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.

The dialysis tubing itself represents the cell membrane.

The dialysis tubing is selectively permeable because substances such as water, glucose, and iodine were able to pass through the tubing but the starch molecule was too large to pass.

Glucose, starch and iodine (potassium iodide) will readily pass through the membrane of the dialysis tubing.

The Dialysis tubing provides a semi-permeable membrane. Only allowing smaller molecules to pass through it. Iodine molecules are small enough to pass freely through the membrane, however starch molecules are complex and too large to pass through the membrane. Thus iodine diffused into the tube with the starch.

Starch does not pass through the synthetic selectively permeable membrane because starch molecules are too large to fit through the pores of the dialysis tubing.

Dialysis tubing, also known as Visking tubing, is an artificial semi-permeable membrane tubing used in separation techniques, that facilitates the flow of tiny molecules in solution based on differential diffusion.

The Visking tubing of the model gut represents the wall of the small intestine.

Like a cell membrane, dialysis tubing has a semi-permeable membrane, which allows small molecule to permeate through the membrane. Thus, the dialysis tubing mimics the diffusion and osmosis processes of the cell membrane (Alberts, 2002).

It is important to note that every molecule is different; the concentration, interactions, and hydrophobicity of molecules can influence their ability to diffuse through a dialysis membrane. The temperature, volume, agitation rate and frequency of exchange of the external buffer are also important factors.

Did sugar stay within the dialysis tubing or move out of the tubing? Support your answer with the observations you recorded in Data Table 4. The starch stayed within the dialysis tubing. The IKI solution did not change in color.

There was no change in the transport rate because glucose is transported independently.