Diffusion

Diffusion

1. Diffusion in plants

   • Carbon dioxide gas diffuses in to the leaf
     • Through the Stomata
       • Finds its way to the photosynthesising cells
         • It is then all used up
           • Oxygen produced by photosynthesis
             • Concentration is higher in the leaf than the surroundings
               • It then diffuses out of the Stomata

2. Diffusion in the cell membrane

   • Carbon dioxide and oxygen can easily pass through the thin layer of cell membrane
     • Cell membrane is permeable

3. Diffusion in animals

   • Oxygen diffuses across the thin cell walls of the alveoli of mammals
     • Into the blood
       • Oxygen travels around the body in the blood stream
         • Then diffuses across membranes of respiring cells
           • Carbon dioxide diffuses in the opposite direction
   • Lungs have adapted to have many alveoli
     • Thus increasing the surface area available for diffusion