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Learn about diffusion, osmosis, facilitated diffusion, active transport, and filtration in cells. Explore how substances move across membranes without energy, the types of cellular transport, concentration gradients, isotonic, hypertonic, and hypotonic solutions, and the role of transport proteins.
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Cellular Transport Diffusion Osmosis Facilitated Diffusion Active Transport Filtration
Passive Transport • NO ENERGY REQUIRED to move substances across membrane -- water, lipids, and other lipid soluble substances. • Types: • Diffusion • Osmosis • Facilitated Diffusion • Filtration
Diffusion • Occurs because of Brownian Motion, i.e., the random movement of particles. • Net movement of particles from an area of greater concentration to an area of lesser concentration. • Concentration gradient, i.e., the difference in concentration across space.
Diffusion Molecules move down the concentration gradient until there are equal numbers of molecules on both sides ~ dynamic equilibrium.
Dynamic Equilibrium Molecules continue to move randomly because of Brownian motion, but there is no net movement.
Osmosis • Diffusion of water from an area of greater concentration of water to an area of lesser concentration of water -- across a semipermeable membrane. • Isotonic Solutions • Hypertonic Solutions • Hypotonic Solutions
Isotonic Solution • Concentration of solutes in the solution is the same as inside the cell. • Cell is in dynamic equilibrium, i.e., no net gain or loss of water. H20 H20
Hypotonic Solution • Concentration of solutes is lower in solution than inside cell. • Net movement of water will be INTO the cell. H20 H20 H20
Hypotonic Solution Turgor Pressure -- This is why grocery stores spray vegetables -- crispness! Plant Cell Cytolysis -- Animal cell bursts. Animal Cell
Hypertonic Solution • Concentration of solutes is greater in solution than inside cell. • Net movement of water will be OUT OF the cell. H20 H20 H20
Hypertonic Solutions • Meat placed in salt water loses moisture and is dry and tough when cooked. • Plant cells placed in salt water shrink, losing turgor pressure ~ plasmolysis. • Blood cells in hypertonic solutions will lose liquid ~ plasmolysis.
Facilitated Diffusion • Movement across the membrane with the help of transport proteins . • Types: • Carrier protein - its shape fits certain molecules. • Channel protein- molecules diffuse through channel.
Active Transport • Transport of materials against (low to high) a concentration gradient • REQUIRES ENERGY! • Large Molecules: • Endocytosis/Exocytosis • Molecule engulfed by portion of membrane. • Portion breaks off as vacuole inside cell. • Liquid = Pinocytosis • Solids = Phagocytosis
Active Transport • Sodium-Potassium Pump • transports sodium ions out of cell, potassium ions into cell. High Potassium K+ High Sodium Low Potassium Na+ Low Sodium
Review • Types of Cellular Transport • Diffusion: Movement of solute (high to low) • Osmosis: Movement of water (high to low) • Hypotonic, Isotonic, and Hypertonic • Facilitated Diffusion: Carrier and channel proteins; Does not require energy • Filtration • Active Transport -- Requires energy • Endocytosis, Pinocytosis, Phagocytosis, Exocytosis, Some Carrier Molecules (Sodium-Potassium Pump)
