# Diffusion. Brownian Motion Molecules are constantly moving.

## Presentation on theme: "Diffusion. Brownian Motion Molecules are constantly moving."— Presentation transcript:

Diffusion

Brownian Motion http://www.inventioneeringco.com/commentary-files/brownian_motion.swf Molecules are constantly moving.

Concentration The amount of substance in a defined area.

Gradient Uneven concentrations across a space.

Concentration Gradient When molecules move “with the concentration gradient” they move from area of high concentration to low concentration. When molecules move “against the concentration gradient” they move from area of low concentration to high concentration.

Label the pictures…. _________________________

Diffusion What is it?

Diffusion The movement of molecules from high concentration to lower concentration. Spreading out. http://www.wisc- online.com/Objects/ViewObject.aspx?ID=AP19 03 http://www.stolaf.edu/people/giannini/flashan imat/transport/diffusion.swf

Equilibrium What is it?

Equilibrium Even concentration of substance in a space. http://student.ccbcmd.edu/courses/bio141/le cguide/unit1/prostruct/passive_flash.html

Which picture shows diffusion? _________________________

Think back to the Starch/Iodine Demo……. What happened? Why?

Now complete the starch/iodine review using our new terms!

So, to summarize… Molecules are constantly ____________________. This is called ________________________.

So, to summarize… When there are lots of molecules close together they are ______________ concentrated.

So, to summarize… Since molecules constantly bump into one another, they tend to spread out. The spreading out of molecules is called __________________.

So, to summarize… This happens when there are more molecules on one side of a membrane than on the other. This uneven distribution of molecules is called a ________________.

So, to summarize… The result of diffusion is an even spacing of molecules which is called ____________________.

So, to summarize… The cell membrane decides what molecules can diffuse across based on ______________.

So, to summarize… Because only some molecules can go across, it is called a ________________________ membrane.

So, to summarize… This trait allows the cell membrane to do its main job of ______________________.