1. 2.4 Diffusion

2. Atoms, ions, molecules Atom – smallest particle
Ions – atoms that gain or loose electrons
Molecules – atoms that are chemically bonded
Hydrogen Atom
Hydrogen Ion
Hydrogen Molecules

3. Movement of molecules Solid – molecules vibrate in position
Liquid – molecules vibrate further apart
Gas – molecules vibrate even further
Diffusion: movement of molecules from a high concentrated area to a low concentrated area

4. Image of diffusion

5. Concentration Gradient

6. Gas exchange in humans You breath in air
Oxygen you breath goes into your lungs (Alvioli – sacks within the lungs where gas is exchanged)
Oxygen is absorbed into red blood cells and carbon dioxied is released into the alvioli.
Oxygen in the blood is taken to all the cells
Carbon dioxide is breathed out
The movement of oxygen and carbon dioxide is diffusion.
No energy is needed
Oxygen moves from high concentrated to low concentrated area
Carbon dioxide moves from a high concentrated area to a low concentrated area
Blood is moving in the capillaries (thin layer of cells where blood flows through)

7. Gas exchange in Plants
Palisade and spongy mesophyll photosynthesis using water and carbon dioxide in the air during the day.
With sunlight , carbon dioxide and oxygen , the plant makes sugar and eventually turns it into starch.
0.04% of air is carbon dioxide.
By random chance these carbon dioxide molecules will move into the leaf via the stomata
There is more CO2 outside the leaf than inside .
The concentration gradient exists that shows CO2 on the outside more than the inside.