1. Passive & Active Transport
Tuesday:
October 21, 2014
Passive & Active
Transport
EGGperiment
Osmosis vs Diffusion
Passive & Active Transport
EXIT Slip: Quiz

2. Egg Lab Experiment Egg Type Observation of Egg Observation of Liquid
Hypothesis:
What do you think is happening?
Distilled Water
Air
Karo Syrup
Colored Water
Vinegar
If you were absent during the egg demonstration, you can check it out on YouTube or:

3. Egg Lab Write-Up Review 1. What is osmosis? Conclusion Analysis
2.     Describe what your teacher did to the eggs.    
3.     Describe what happened to each egg in the different liquids?    
4.     Compare the weights of the eggs. Which is the largest weight, which is the smallest?
Conclusion
5.     Why do you think the egg in the water looks like it does?  
6.     Where do you think the water molecules were more crowded, outside or inside the egg with water? Why? 
7.     Why do you think the egg in the syrup looks like it does?    
8.     Where do you think the water molecules were more crowded, outside or inside the egg in the syrup? Why?
These questions should be answered in complete thoughts in your Science Notebook. 

4. Cells using diffusion and osmosis to move stuff through cell membranes is like riding a bike downhill!
So remember…
Have you ever ridden a bicycle down a long hill? Does it take a lot of energy to go fast?
What about riding a bike uphill? Does it take a lot of energy to go fast?

5. Passive Transport: moving dissolved stuff through the cell membrane without using cellular energy – like riding a bike downhill

6. simply the diffusion of water
Osmosis
Osmosis: Osmosis is simply the diffusion of water; it has its own name because water is so important to life. Solutions with higher amounts of dissolved substances have lower concentrations of water, and water will diffuse across membranes in order to minimize the difference in concentration.
simply the diffusion of water

7. Active Transport
2 Methods

8. Gradient = direction of the concentration of molecules balancing
A gradient is the change in the value of a quantity (e.g., concentration, pressure, temperature) with the change in another variable (e.g., distance). For example, a change in concentration over a distance is called a concentration gradient, a change in pressure over a distance is called a pressure gradient, and a change in temperature over a distance is a called a temperature gradient.

9. 2. Diffusion
Diffusion is the movement of molecules from a crowded area to a less crowed area. In cells molecules move through tiny holes in the cell membrane. Only molecules small enough to fit through the holes are let in.

10. Active Transport – is the movement of materials through a cell membrane using cellular energy – like riding a bike uphill
Transport Proteins – these proteins “pick up” molecules outside the cell and carry them in, using energy – ex: calcium, potassium, sodium
Sometimes, much-needed nutrients or harmful substances must be transported across the membrane against a concentration gradient. In these cases, the cell must provide energy in order to move the material against the direction of diffusion. This kind of energy-requiring transport is called active transport and, like facilitated diffusion, uses membrane proteins. Often, these proteins cleave ATP in order to obtain the needed energy. Other proteins use the energy released from the diffusion of one substance to power the active transport of another substance. (Osmosis for Dummies online).

11. Active transport requires the cell to use its own energy…
Passive transport does NOT
**Active transport requires the cell to use its own energy, while passive transport does not!**

12. Transport by Engulfing – the cell membrane surrounds and engulfs, or ‘eats’, a particle. Once the particle is engulfed, the cell membrane wraps around the particle and forms a vacuole within the cell