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Cell Transport. Chapter 5. Cell Transport. Passive Transport. Active Transport. Passive Transport. Passive transport requires no energy Particles or water move down the concentration gradient From a high to a low concentration
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Cell Transport Chapter 5
Cell Transport Passive Transport Active Transport
Passive Transport • Passive transport requires no energy • Particles or water move down the concentration gradient • From a high to a low concentration • Concentration gradient: difference in amount of molecules over a space.
Kinds of Passive Transport • Diffusion • Facilitated Diffusion • osmosis
Diffusion • Diffusion: the movement of particles from an area of higher concentration to an area of lower concentration.
Diffusion Goal • Dynamic Equilibrium: equal amounts throughout the same space (but still moving) • Three Key Factors that effect Diffusion • Concentration • Temperature • Pressure
Facilitated Diffusion • Facilitated = helped. • Occurs when a substance can not go directly through a membrane even with the concentration gradient. • Glucose is large and needs help getting across the cell membrane. • Carrier proteins • NO ENERGY!!
Osmosis • Specialized Diffusion • Osmosis: the movement of water from an area of higher concentration to an area of lower concentration.
Osmosis • Isotonic • Same amount of salt in the cell as out of the cell • Water will move equally in and out of the cell • Dynamic equilibrium • Freshwater protist in Lake Norman
Osmosis Cont. • Hypotonic • More salt inside the cell than outside the cell. • Water will move into the cell. • Cell may burst • cytolysis Example: Saltwater protist placed in fresh water.
Osmosis Cont. • Hypertonic • More salt outside the cell than inside the cell. • Water will move out of the cell. • Cell shrivels • Plasmolysis • Example: fresh water protist placed in salt water.
Cell Transport No Energy Passive Transport Active Transport Movement of particles down a concentration gradient Diffusion Movement of water down a concentration gradient Osmosis Diffusion w/ the help of a carrier protein Facilitated Diffusion
Active Transport • Requires the cell to use energy. • Moves materials against the concentration gradient. • 3 Types • Pumps (Na+ - K+ Pump) • Endocytosis • Exocytosis
Na+ - K+ Pump • Sodium is pumped (energy) out. • Potassium comes in as a byproduct.
Endocytosis • Uses energy to pinch in the plasma membrane to bring in large quantities of food particles.
Exocytosis • Uses energy to remove large quantities of waste by fusing a vesicle to the plasma membrane.
Cell Transport Needs Energy Active Transport Passive Transport Uses energy to move Na+ out of the cell against the concentration gradient. Na+- K+ Pump Diffusion Pinches plasma membrane to bring in large amounts of stuff. Endocytosis Osmosis Fuses vesicle to plasma membrane to rid the cell of stuff. Facilitated Diffusion Exocytosis