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Explore the structure and function of the cell membrane and cell wall, learn how diffusion occurs, predict cell behavior in different environments, and define active transport.
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Cell Boundaries Content Objectives: Compare & contrast the structure and function of the cell membrane & cell wall. Explain how diffusion occurs. Predict what happens to a cell in hypertonic, hypotonic, & isotonic environments. Define active transport.
All cells have a Cell Membrane! • Cell membrane – a thin, flexible boundary that surrounds all cells. • The cell membrane controls what enters and leaves the cell and provides protection & support! Animal Cell Cell Membrane
What are Cell Membranes made of? • Cell membranes are made of two layers of lipids, called a lipid bilayer. • The cell membrane also contains proteins that move materials in or out of the cell.
CELL WALLS – FOUND IN PLANT CELLS, ALGAE, AND FUNGI • Cell walls – strong supporting structures around the cell membrane. • The main function of the cell wall is to support and protect the cell. • Cell walls are made of carbs and proteins. Plant Cell Cell Membrane Cell Wall
Diffusion • Diffusion – particles tend to move from areas of high concentration to areas of low concentration. • When the concentrations are the same on both sides, it has reached equilibrium. Animal Cell NO ENERGYREQUIRED!!
Facilitated Diffusion • Facilitated Diffusion – the cell membrane helps the diffusion of a substance. • Cell membrane uses protein channels. Animal Cell NO ENERGYREQUIRED!!
Osmosis • Not all substances can cross cell membranes. • MEMBRANE: • Permeable = can be crossed • Impermeable = cannot be crossed • Osmosis - the movement of water across a selectively permeable membrane.
How Does Osmosis Work? • Hypertonic – more concentrated Water Plasmolyzed!! Animal Cell
How Does Osmosis Work? • Hypotonic – less concentrated Water Animal Cell
How Does Osmosis Work? • Isotonic – equal concentrations Water Water Animal Cell
Active Transport • Active Transport – the cell membrane moves materials AGAINST the concentration gradient. • Cell membrane uses protein channels to pump things in or out. Animal Cell ENERGY ISREQUIRED!!
Cell Boundaries Content Objectives: Compare & contrast the structure and function of the cell membrane & cell wall. Explain how diffusion occurs. Predict what happens to a cell in hypertonic, hypotonic, & isotonic environments. Define active transport.