Perspective If a Hydrogen atom were the size of a penny A penny would be the size of the moon!

Cells, Transport and Homeostasis How cells get what they need (and not what they don’t need).

Diffusion How could/can you smell the fish tank (when it’s yucky) from where you sit? Diffusion particles moving from an area of higher concentration to an area of lower concentration WHY do molecules diffuse? THINK about it.

Diffusion How could/can you smell the fish tank (when it’s yucky) from where you sit? Diffusion particles moving from an area of higher concentration to an area of lower concentration WHY do molecules diffuse? THINK about it. What factors would influence the rate of diffusion?

Diffusion When do the molecules stop moving? Think about it! Why is no additional energy needed for diffusion? Is diffusion good for cells? Explain.

Diffusion Almost any molecule will diffuse across a cell membrane… given enough time Small molecules diffuse faster O 2, CO 2 Water, but it takes a little longer

Diffusion How could you make it work better? Facilitated Diffusion – Particles diffusing across a membrane through specific transmembrane proteins.

Facilitated Diffusion

Ions and molecules moving across the membrane via transmembrane proteins Channels and carrier proteins Channels allow things through (not much control). Carrier proteins move things through (more control).

Gated Channel = Carrier

Facilitated Diffusion Diffusion and Facilitated Diffusion are both passive transport… Movement of particles across a cell membrane without the need of additional energy

And within your lifetime… Aquaporin

Make a prediction about an aquaporin’s structure/makeup

Aquaporin Make a prediction about an aquaporin’s structure/makeup

Diffusion vs Osmosis What is the difference between diffusion and osmosis? How does osmosis happen?

Homework Provide three examples of particles that need to be moved in to/out of a cell