Passive Transport Lab


To visualize diffusion of molecules across a semipermeable membrane

To determine which molecules were permeable to the dialysis tubing

To relate the diffusion of molecules across the dialysis tubing to diffusion across a plasma membrane

To identify (3) factors that contribute



Most hypothesized the following:

Glucose moves out of the dialysis bag b.


Starch moves out to the dialysis bag

Iodine moves into the dialysis bag

“Why did people think this would happen?”

2. A few hypothesized that starch molecules would not move out of the dialysis bag.

“Why would a few think this?”

Starch diffused out or stayed in bag – Iodine

Iodine reacts with starch and turns blue-black

Observe setup and complete Table 1

Glucose diffused out of bag – Benedicts


Benedicts reacts with glucose and turn organge.

Add about two droppers of beaker water to test tube

Add Benedicts to test tube to make water blue

Place in hot water bath

Record observation in Table 2

Complete Analysis Questions #1-5

This is after the dialysis bag that was filled with a glucose and starch solution looked like after 60 minutes.

This is what the setup looked like after 24 hours.

This is a tube of beaker solution and Benedict’s solution. Note the orange color that looks like carrot juice. Yum, yum!