Presentation on theme: "Cellular Transport Passive Transport Movement of molecules across the membrane No energy needed High to low concentration Ex: diffusion, osmosis, facilitated."— Presentation transcript:
Passive Transport Movement of molecules across the membrane No energy needed High to low concentration Ex: diffusion, osmosis, facilitated diffusion
Diffusion Robert Brown – Scottish scientist in 1827 discovered Brownian motion. ▫Random movement of molecules Movement from high to low concentration.
Diffusion Affected by: ▫Concentration – the higher the concentration, the faster it diffuses; the lower the concentration, the slower it diffuses. ▫Size and type of molecule ▫Temperature – the warmer the temperature, the faster it diffuses; the colder the temperature, the slower it diffuses.
Dynamic Equilibrium Reached when movement in the cell is equal to the cell balance
Osmosis Movement of water molecules through a selectively permeable membrane Types of diffusion ▫Isotonic solution – movement same in and out ▫Hypotonic solution – gain turgor pressure, swells and may burst ▫Hypertonic solution – loss of turgor pressure, water leaves cell, shrinkage occurs Plasmolysis (cell wilts)
Diffusion Process IN food carbohydrates sugars, proteins amino acids lipids salts, O 2, H 2 O IN OUT waste ammonia salts CO 2 H2OH2O products
Facilitated Diffusion Use Transport Proteins that span the cell membrane Transport proteins ▫Channel proteins: provides tube-like opening in the plasma membrane through which particles can diffuse ▫Carrier Protein: changes shape “The Bouncer”