1. What does the tubing represent?

2. What is inside the tubing?

A selectively permeable cell membrane.

Starch & glucose solutions

3. What did we add to make the liquid outside the “cell” amber colored?

Starch indicator (Lugol’s iodine)

4. Why does the inside of the “cell” turn purple or black?

Starch indicator (Lugol’s iodine) diffused into the tubing

High iodine concentration Low iodine

concentration

5. How do we know that starch did not move from the inside to the outside?

No color change outside the cell in the beaker.

6. How can we find out if glucose moved into the beaker?

Glucose (high conc.)

?

Do a glucose indicator (Benedict’s) test using the fluid in the beaker

7. After placing 10 drops of the amber colored beaker solution into a test tube, what do we add to it?

Glucose indicator (Benedict’s solution)

8. After adding the glucose indicator solution (blue) what do we do with the test tube?

Heat it in the hot water bath.

9. If there is glucose in the solution, what will happen to the blue color after heating the tube for 2 minutes?

The color changes to green with trace amounts of glucose, and then to an orange/red with a greater amount of glucose.

10. The blue color changed to orange. This means that what substance is in the test tube?

glucose

11. Glucose indicator solution was added to these test tubes, and then the tubes were heated. Which will change color?

starch glucose C6H12O6

Were you right?