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Transcript
Cellular Transport Involves the absorption and circulation of materials Plasma Membrane controls the movement of molecules into or out of the cell Selectivity Permeable ( Based on SIZE of Molecules ) Monomers- Small Polymers - Big Plasma Membrane – materials ENTER the cell circulation – materials are moved throughout the cell cyclosis – the circulation of the cytoplasm cyclosis animation absorption Fluid Mosaic Model of Plasma Membrane flexible structure made up primarily of lipids and proteins Membrane movement animation Proteins proteins are embedded in the bilayer: transport proteins help some substances move in or out Types of Cellular Transport I. Passive Transport Weeee!! ! no energy required no cellular energy required A. Diffusion B. Osmosis C. Facilitated Diffusion high low A. Simple Diffusion Passive Transport A. Simple Diffusion Simple Diffusion substance passes through a membrane without the aid of transport proteins Simple Diffusion there is a net movement of molecules from areas of high concentration to areas of low concentration Concentration Gradient molecules move with the concentration gradient Molecules that are able to diffuse: Oxygen Carbon dioxide Water Simple Diffusion diffusion stops once molecules are evenly distributed = dynamic equilibrium molecules are still in constant motion, but same number of molecules move in one direction as in the opposite direction B. Osmosis diffusion of water through a selectively permeable membrane water moves from a high to a low concentration 1. Hypotonic Solutions have a lower concentration of solutes (dissolved substances) and a higher concentration of water than inside the cell Hypotonic Solutions Result: water moves from the solution to inside the cell: cell swells and bursts open (cytolysis)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutions 2. Hypertonic Solutions have a higher concentration of solutes (dissolved substances) and a lower concentration of water than inside the cell Result: water moves from inside the cell into the solution: cell shrinks (Plasmolysis)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Osmosis animation Hypertonic Solutions 3. Isotonic Solutions the concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium) What type of solution are these cells in? A B C Osmosis in animal cells Osmosis in plant cells Adaptations for Freshwater Protists paramecium has contractile vacuoles that collect water flowing in and pump it out to prevent them from overexpanding. contractile vacuoles C. Facilitated Diffusion D. ( St diffusion of specific particles through transport proteins found in the membrane transports larger molecules Channel Proteins animations Facilitated Diffusion II. Active Transport Requires cellular energy (ATP) This is gonna be hard work!! high A. Protein Pumps B. Endocytosis C. Exocytosis low Active Transport used to transport large molecules through a membrane –or to move molecules against the concentration gradient (low→ high concentration) A. Protein Pumps Example: Sodium / Potassium pumps are important in nerve responses. Sodium Potassium Pumps (Active Transport using proteins) Protein changes shape to move molecules: this requires energy! B. Endocytosis forming vacuoles to bring molecules into a cell 1. Phagocytosis “cellular eating” pseudopods (false limbs) are formed cell membrane and cytoplasm extend outward to engulf a large particle Phagocytosis 2. Pinocytosis “cell drinking” plasma membrane takes in particles dissolved in fluid when cell membrane forms small channels C. Exocytosis vacuole moves to the plasma membrane and fuses with it to spill contents outside of cell •Animations of Active Transport & Passive Transport