PASSIVE TRANSPORT Osmosis Diffusion and Facilitated Diffusion HOMEOSTASIS

PASSIVE TRANSPORT Osmosis, Diffusion, and Facilitated Diffusion

HOMEOSTASIS v The purpose of the cell membrane is to help the cell maintain homeostasis… v A constant internal condition v It allows the cell to control what enters and what leaves

PASSIVE TRANSPORT v Some molecules can easily cross the membrane v Water, oxygen and carbon dioxide

THREE FORMS OF PASSIVE TRANSPORT v 1. Diffusion— • Movement of molecules from high to low concentration • The difference in these areas is called the concentration gradient • Does not require energy • Rate depends on temperature, size and type of molecule • Faster at high temps, smaller, and short distance • Continues until even on both sides

THREE FORMS OF PASSIVE TRANSPORT v 2. Osmosis— • Movement of water • High to low concentration (less to more water) • Does not require energy • Will occur until equal

3 TYPES OF OSMOTIC SOLUTIONS v Hypertonic Solution • Solute higher outside the cell • Water will diffuse out of the cell until equilibrium • Cells will shrink and die

3 TYPES OF OSMOTIC SOLUTIONS v Hypotonic • • Solute concentration is higher inside (less water) Water moves into the cell until equal Animal cells will swell and burst Plants work best in this environment

3 TYPES OF OSMOTIC SOLUTIONS v Isotonic • Concentration of solute same inside and outside • Water moves in and out freely • Animal cells work best

3 FORMS OF PASSIVE TRANSPORT v 3. Facilitated Diffusion • Faster than normal diffusion • No energy required • High to low concentration • Uses carrier proteins embedded in the membrane and channel proteins

THE END v