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Learn about cell membrane structure, transport methods like diffusion and osmosis, concentration gradients, and permeability. Understand the role of solutes and solvents in cellular processes.
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Cell Membrane • Definition: The semi-permeable outer-covering of all cells. • Composition: • 2 Phospholipid Layers • Protein Channels embedded • Purpose / Function: • Control traffic in and out of the cell • Protection
Cell Wall • Definition: The rigid outer-covering of plant, and some bacterial cells. • Composition: • Cellulose (Plants) • Chitin (Fungi) • Peptidoglycan (Bacteria) • Purpose / Function: • Extra Support & Structure • Extra Protection
Cell Membrane Transport • Methods: • Diffusion (No energy needed) • Osmosis (No energy needed) • Active Transport (Energy needed) • “Transport” = Things moving in and out of the cell.
Concentration • Definition: The amount of matter in a given amount of space (area). • High Concentration = More matter in a given amount of space. • Low Concentration = Less matter in a given amount of space. • “Concentration Gradient”: A difference in concentrations.
Permeability • Definition: The ability of matter to move across a boundary. • Cell Membranes are Semi-Permeable. • “Semi-Permeable”: The ability of only certain types of matter to move across a boundary.
Fully Permeable Not Permeable Semi- Permeable
Equilibrium • Definition: State of balance. • Matter moves in and out of cells to reach equilibrium.
Diffusion • Definition: The movement of particles across a concentration gradient, from an area of higher concentration, to an area of lower concentration.
Osmosis • Definition: The movement of water particles, across a concentration gradient, from an area of higher water concentration, to an area of lower water concentration. • *Water concentration with respect to Solute concentration!
Solute & Solvent • Solute: Solid particles • Sugar • Salt • Solvent: Liquid which dissolves solute. • Water