What cell structure the dialysis tubing represents?

The dialysis tubing represents the cell membrane.

Dialysis tubing is a semipermeable membrane, just like the cell membrane. It allows some molecules to pass through it while blocking others. In a dialysis experiment, the dialysis tubing is filled with a solution of molecules of different sizes. When the dialysis tubing is placed in a beaker of water, the water molecules can pass through the membrane and into the tubing, while the larger molecules cannot. This process is similar to how the cell membrane allows some substances to enter and leave the cell while blocking others.