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Types of Transport Across Cell Membranes. Essential Question. Compare/Contrast active/passive transport How do we make spaghetti noodles soft? What is the purpose of cell transport ?. Passive Transport. Requires NO energy Molecules move from area of HIGH to LOW concentration.
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Essential Question Compare/Contrast active/passive transport How do we make spaghetti noodles soft? What is the purpose of cell transport?
Passive Transport • Requires NOenergy • Molecules move from area of HIGH to LOWconcentration
Passive Transport: Diffusion • Diffusion is a PASSIVEprocess • Molecules move DOWN the concentration gradient
Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW)
Essential Question Explain diffusion
Passive Transport: Osmosis Diffusion across a membrane • Diffusion (passive transport) of wateracross a membrane • Moves from HIGH water potential(low solute) to LOW water potential(high solute) Semipermeable membrane
Passive Transport: Osmosis across a membrane High H2O potentialLow solute concentration Low H2O potentialHigh solute concentration
Cell in Isotonic Solution 10% NaCL90% H2O ENVIRONMENT CELL NO NET MOVEMENT 10% NaCL 90% H2O What is the direction of water movement? equilibrium The cell is at _______________.
Cell in Hypotonic Solution ENVIRONMENT 10% NaCL90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement?
Cell in Hypertonic Solution 15% NaCL85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O What is the direction of water movement?
Isotonic Solution Hypotonic Solution Hypertonic Solution NO NET MOVEMENT OF H2O (equal amounts entering & leaving) CYTOLYSIS PLASMOLYSIS
Cytolysis & Plasmolysis Plasmolysis Cytolysis
Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic
hypotonic hypertonic isotonic hypertonic isotonic hypotonic
Essential Question How do we make spaghetti noodles soft?
Passive Transport Review • Diffusion/Osmosis • NO ENERGY required • Moves high to lowconcentration • Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.
Passive Transport • Facilitated diffusion • NO ENERGY required • Uses transport proteinsto move high to low concentration • Examples: Glucose or amino acids moving from blood into a cell.
Passive Transport: Facilitated Diffusion Proteins Are Critical to Membrane Function
Passive Transport: Facilitated Diffusion • Types of Transport Proteins: • Channel proteins are embedded in the cell membrane & have a pore for materials to cross • Carrier proteins can change shape to move material from one side of the membrane to the other
Facilitated Diffusion(Channel Proteins) Molecules will randomly move through the pores in Channel Proteins.
Facilitated Diffusion (Carrier Proteins) • SomeCarrier proteins do not extend through the membrane. • They bond and drag molecules through the lipid bilayer and release them on the opposite side.
Facilitated Diffusion (Carrier Proteins) • Other carrier proteins changeshapeto move materials across the cell membrane
Essential Question Explain Facilitated Diffusion
Active Transport • Requires energy or ATP • Moves materials from LOW to HIGH concentration • AGAINST concentration gradient
Active transport • Example:Sodium Potassium Pump • Pumping Na+ (sodium ions) out and K+ (potassium ions) in against strong concentration gradients.
Sodium-Potassium Pump 3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential
Moving the “Big Stuff” Exocytosis-moving things out. Molecules are moved out of the cell by vesicles that fuse with the plasma membrane. This is how many hormones are secreted and how nervecellscommunicate with one another.
Receptor-Mediated Endocytosis Some integral proteins have receptors on their surface to recognizeand take inhormones, cholesterol, etc. to communicate
Essential Question Explain Active Transport
What’s the point? • To maintain homeostasis=balance
Essential Question Compare/Contrast active/passive transport How do we make spaghetti noodles soft? What is the purpose of cell transport?