1. NYSED Part D Lab Review

2. Diffusion

3. Osmosis

4. Part 2: Create a “cell” What’s the name of the bag?
What does it represent?
What were the chemicals in the bag?
What chemical was in the beaker?
Wait about 15 minutes and observe.
Insert into “cellular environment”

5. Science Experiment - Diffusion Through a Membrane - YouTube

6. Part 1: Diffusion
Diffusion: movement of ______________molecules from an area of _____________ concentration to an area of _________ concentration ____________energy
After diffusion occurs…
Before diffusion occurs…

7. After 15 minutes, observe…
What happened to the glucose in the “cell”? why? S S G I G G G I I G I G I S S I I I
At the beginning…
After 15 minutes…

8. After 15 minutes, observe…
What happened to the the starch in the “cell”? Why? S S G I G G G I I G I G I S S I I I
At the beginning…
After 15 minutes…

9. After 15 minutes, observe…
What happened to the Lugol’s iodine outside the “cell”? Why? S S G I G G G I I G I G I S S I I I
At the beginning…
After 15 minutes…

10. What is starch indicator?
What is glucose indicator?

11. How did you know that the Iodine went into the bag?
What 2 solutions mixed together made it that color?

12. When you mix Iodine with distilled water the color turns ___________
When you mix Iodine with glucose, the color turns ______________
When you mix Iodine with starch, the color turns __________

13. How do you test for the presence of glucose?

14. When you mix Benedict’s with distilled water the color turns ___________
When you mix Benedict’s with starch, the color turns ______________
When you mix Benedict’s with glucose, the color turns __________

15. And now, the part that makes you cry (ok, not really, but the “Red Onion” part of the lab)…
Prepare a wet mount slide of the inner epidermis of a red onion section;
Observe the red onion and draw what you see;
Add a couple of drops of saline (salt) solution to the epidermis. Wait 5 minutes;
Observe under microscope again, note any changes;
Add freshwater to the slide, wait 5 minutes, observe changes again.

16. Plasmolysis in Red Onion (Techno) – YouTube

17. Red Onion Plasmolysis Observation
Before and after observations of red onion epidermis under the microscope (400X)
Red onion under in hypertonic (salt) solution. Note cell membrane has “withdrawn” and the cytoplasm has lost water to the salty environment, making it appear smaller and darker.
Red onion under in isotonic (normal) solution. Note cell membrane and cytoplasm almost completely “fill” the boundary of the cell wall.