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Diffusion & Osmosis. Objective 2.03 Movement of materials into and out of cells. Passive Transport. Passive Transport : Movement within the cell that does not cost the cell any energy (ATP).
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Diffusion & Osmosis Objective 2.03 Movement of materials into and out of cells.
Passive Transport • Passive Transport: Movement within the cell that does not cost the cell any energy (ATP). • Diffusion: The movement of particles from an area of high concentration to an area of low concentration. • Diffusion is free for the cell. • When the equilibrium is reached, the cell is in homeostasis. Diffusion Clip
Passive Transport • Facilitated Diffusion: a.k.a. “Helped” diffusion. The large protein channels help bring larger molecules that can’t squeeze through the cell membrane into the cell. This process is “free” to the cell and does not require the cell to use energy ATP. Facilitated Diffusion Clip
Transport Proteins • There are 2 types of transport proteins: • Channel Proteins = cannot change shape (a) • Carrier Proteins = can change shape (b)
Passive Transport • Osmosis: The diffusion of water across a semi permeable membrane. • This process if free for the cell also. Does NOT cost the cell energy (ATP). Hypertonic Isotonic Hypotonic (Cell Shrinks) ( Dynamic Equilibrium) (Cell Swells) 65% Salt Solution 20% Salt Solution 50% Salt Solution 90% Salt Solution 50% Salt Solution 10% Salt Solution
Cells in Solutions Bursts Shrivels Turgor Pressure – Plasmolysis- cell membrane “pushes” cell membrane pulling on cell wall away from cell wall
Active Transport • Active Transport: Cells force molecules AGAINST the concentration gradient. • This process costs the cell energy (ATP)! • Protein Chanels and Pumps are used to move these molecules.
