4.1 Cell Biology Lesson 7

Baseline (flightpath D): Know that molecules move into and out of a cell through its membrane by a process called diffusion and give an example of one substance that does this. Further (flightpath C): Describe how relative concentrations affect the direction of diffusion through the cell membrane and give an example of a factor that affects the rate. Challenge (flightpath B&A): Explain in detail factors that affect the rate of diffusion and how the body utilises this to increase the diffusion rate of important substances.

What substances have to move into or out of a cell?

Which way are the carbon dioxide molecules going to travel? Why?

Which way are the oxygen molecules going to travel? Why?

area of high concentration to an area of low concentration Oxygen molecule The oxygen molecules will move down their concentration gradient from an area of high concentration to an area of low concentration