Distinguish between

diffusion and osmosis Know how particles move in

and out of cells

Points

The movement of particles from areas of higher concentration to areas of lower concentration is diffusion.

Diffusion is one way that materials are exchanged between a cell and its environment

Diffusion

Water is very important to the cells of

organisms. The diffusion of water across cell membranes is called osmosis.

The concentration of particles important to cell functions are kept in balance by osmosis.

Osmosis

With your group come up with 4

examples of osmosis or diffusion (total of 4)

One stray Stayers – list your examples Strayer – pick your favorite

example from the group you visit

Activity

What is Equilibrium? Static equilibrium: no change in the system

is occurring.

For example, a bucket of water is in equilibrium because there is no change occurring to it.

What is Equilibrium?

For example, a bucket of water with a hole in it is releasing water. At the same time more water is being poured in the bucket at the same rate it is pouring out.

Dynamic equilibrium: changes in the system are occurring, but at the same rate as one another.

For Example…

Suppose you have a balloon filled with helium. As you know this balloon will not float forever and after a day or so will eventually shrink and remain on the ground.

This is an example of diffusion. The helium slowly escapes the balloon across the surface until the concentration is equal on both sides.

Why is it some balloons float for longer periods of time than others? (answer the question in your notebook)

How is this Important?

Diffusion is an important concept for humans because our very existence depends on it.

The cells of the human body utilize diffusion every day!

Can you think of where in the human body diffusion might be important?

Passive Transport

The movement of particles across a cell membrane by diffusion or osmosis

pHet

Active Transport

The movement of particles across a cell membrane that goes against diffusion

Requires the cell to use energy

The Cell and Osmosisexamples…

Red blood cells are surrounded by plasma Plasma is made of water, salts, sugars

and other particles If placed in pure water, the red blood

cells would burst In a salty solution, the red blood cells

shrivel

Question

Has this ever happened to you?

With the information you just learned, and your previous experience, form a hypothesis of why you think that is…

Are your fingers swelling or shrinking? What do you know about your skin?

Points to consider…