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Introducing Cell Transport. Cell Transport. Concentration Gradient Concentration – The amount of solute in a solution Gradient – A measure of how much something changes when you move from one region to another. Put ‘em together and what do you get?
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Cell Transport • Concentration Gradient • Concentration – The amount of solute in a solution • Gradient – A measure of how much something changes when you move from one region to another. • Put ‘em together and what do you get? • Concentration Gradient - measurement of how the concentration of something changes from one place to another.
Passive Transport • Passive Transport – Molecules moving from an area of high concentration to low concentration. • No energy needed
Diffusion • The process by which molecules spread from areas of high concentration, to areas of low concentration. • Equilibrium – Concentration is equal throughout solution. Diffusion Animation
Osmosis • The movement of water molecules from high concentration to low concentration
Osmosis • Hypertonic: Water diffuses out of cell • (Cell Shrinks) • Hypotonic: Water diffuses into cell • (Cell swells) • Isotonic: Equal rate of water diffusion into and out of the cell • (Cell Stays the Same) • http://staff.jccc.net/aalarabi/memb_related_mov.htm
Facilitated Diffusion A form of diffusion facilitated by transport Proteins also known as carrier proteins
Facilitated Diffusion • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html
Active Transport • Active Transport: The Transport of a substance across the cell membrane against its gradient • Requires Energy ( usually ATP) • http://staff.jccc.net/aalarabi/memb_related_mov.htm
Bulk Transport • Endocytosis- The movement of a substance into a cell by a vesicle • Cell membrane forms pouch around substance and then pinches off
Bulk Transport • Exocytosis- The movement of substance by a vesicle to the outside of a cell • Vesicles fuse with cell membrane
Cells Must Be Small • All substances that enter or leave the cell must cross that cell’s surface • Small cells can exchange substances better than large cells • They don’t have to travel as far to reach the center