0. Starter 9/8/2014 What are some examples of osmosis and diffusion
Starter 9/8/2014 What are some examples of osmosis and diffusion??? Decide whether the situation is isotonic, hypertonic, or hypotonic
Engage – Osmosis/Diffusion Notes
Reflect – Potato Post Lab
OBJECTIVES
Understand more about osmosis and diffusion by taking notes
Understand the results of potato lab

1. Diffusion and Osmosis

2. Diffusion
1. Movement of molecules from areas of high concentration to low concentration. (Concentration Gradient)
2. Driven by the kinetic energy of molecules.
3. Rate continues until Equilibrium is reached.

3. 5. Phospholipids have 2 parts:
4. Solutions can be…
a) Hypotonic (below) solution is the one with fewer solutes.
b) Hypertonic (above) solution is the one with more solutes.
c) Isotonic (same) solutions have equal amounts of solute.
5. Phospholipids have 2 parts:
A. polar, hydrophilic ,“water-loving,” head
B. 2 nonpolar hydrophobic, “water-fearing,” tails

4. Cell Membranes

5. 6. Cell Membranes The proteins carryout most membrane functions
Adhesion Proteins- help one cell adhere to another or to a protein.
Communication Proteins- line up with the identical proteins in the plasma membrane of another cell. The two fuse and form a channel the directly connects the cytoplasm of both.
Receptor Proteins- are docks for hormones and other signaling molecules.

6. 6. Cell Membranes
Recognition Proteins- project above the plasma membrane and identify a cell as self or nonself.
Passive Proteins- have a channel through their interior to assist solutes or water by simply letting them diffuse through the channel (no energy required).
Active Transporters- active transporter proteins pump a solute across the membrane against a concentration gradient.

7. Osmosis
7. Osmosis is the diffusion of water across a selectively permeable membrane, to a region where the water concentration is lower.
8. Water tends to diffuse from a hypotonic fluid into a hypertonic fluid.
9. Diffusion of a solute through a membrane is known as dialysis.

8. 10. Osmosis
ISOTONIC solutions, same solute concentration between the cell and its environment.
Rate of diffusion is at equilibrium with the environment.

9. 10. Osmosis “Hungry, Hungry, Hypo!”
HYPOTONIC solutions, the solution has fewer solutes.
Water concentration is lower inside the cell than out, causing water to diffuse in to the cell from high to low concentration.
Cytolysis – cells swells and bursts
“Hungry,
Hungry,
Hypo!”

10. 10. Osmosis HYPERTONIC solution , the solution has more solutes.
Water concentration is higher inside the cell than out, causing water to diffuse out of the cell from high to low concentration.
Plasmolysis – cell shrinks (dehydrates)

11. Osmosis HYPOTONIC SOLUTION HYPERTONIC SOLUTION ISOTONIC SOLUTIONs
11. Which direction will osmosis occur?
Cell
95% H2O
75% H2O
Cell
95% H2O
99% H2O
HYPOTONIC SOLUTION
HYPERTONIC SOLUTION
Cell
95% H2O
ISOTONIC SOLUTIONs