Active and Passive Transport

Notes Outline I. Compare and Contrast a)Passive b)Active II. Passive Transport a)Diffusion b)Facilitated Diffusion c)Osmosis III. Active Transport IV. Bulk Transport a)Exocytosis b)Endocytosis 1.Pinocytosis 2.Phagocytosis

I. Compare and Contrast Passive Transport – Movement of molecules through the cell membrane which does NOT require energy Active Transport – Movement of molecules through cell membrane which DOES require energy.

II. Passive Transport a)Diffusion: – Natural movement of molecules from HIGH concentrations to LOW concentrations – Uses channel proteins Ex: gas exchange at the alveoli — oxygen from air to blood, carbon dioxide from blood to air. b)Facilitated Diffusion: – Movement of SPECIFIC molecules using a SPECIFIC CARRIER PROTEIN

II. Passive Transport c) Osmosis: – Example of diffusion – Movement of WATER from HIGH concentrations of WATER to LOW concentrations of WATER

II. Passive Transport c) Osmosis: – Solution concentrations 1.ISOtonic: cell has equal amount of solutes as its surroundings 2.HYPERtonic: cell has lower concentration of solutes than its surroundings WATER LEAVES CELL 3.HYPOtonic: Cell has higher concentration of solutes than its surroundings WATER ENTERS CELL

III. Active transport REQUIRES ENERGY = ATP Molecules move from LOW concentrations to HIGH concentrations OR when a cell has to move large particles into or out of the cell – Sodium-Potassium Pump in nerve cells – Re-absorption of glucose, amino acids, and salts in nephron of kidney

IV. Bulk Transport Examples of active transport a)Exocytosis: releasing particles from the cell – Ex: the golgi apparatus packages mucous, hormones, or other proteins and then releases the packages through the plasma membrane

IV. Bulk Transport b) Endocytosis: cell surrounds the substances and then pulls them into the cell 1.Pinocytosis: take in small particles or fluid (Ex: roots 2.Phagocytosis: take in large particles like bacteria or other cells