Presentation on theme: "Cell Boundaries and Movement. Cell Barriers Cell membranes – Structure: contain a flexible lipid bilayer with imbedded protein molecules and carbohydrate."— Presentation transcript:
Cell Boundaries and Movement
Cell Barriers Cell membranes – Structure: contain a flexible lipid bilayer with imbedded protein molecules and carbohydrate molecules – Function: Substances move across the cell membrane through A.) lipid bilayer B.) protein channels C.) assistance of protein molecules D.) Processes of endocytosis and exocytosis
Cell Barriers Cell Walls – Structure: made mostly of tough carbohydrate fiber called cellulose – Function: Cell walls support and protect cells; cell walls are porous and allows substances to move through easily
Types of Movement Through Cells A.) Diffusion B.) Osmosis C.) Facilitated Diffusion D.) Active Transport
Diffusion Substances move across the cell membrane from areas of high solute concentration to areas of low solute concentration until equilibrium is reached No energy required Substances continue to move back and forth across the membrane once equilibrium is reached
Osmosis The diffusion of water across a cell membrane Types of osmotic solutions – Hypotonic – Isotonic – Hypertonic
Concentration Concentration of a solution is the mass of solute in a given volume of solution, or mass/volume A Solute is a substance that is dissolved in a solvent to make a solution
Which way will the water move?
Hypotonic Solution the solution has a lower solute concentration than the cell so water moves into the cell causing plant cells to swell and animal cells to swell and burst Lower solute concentration Lower solute concentration outside cell Animal Cell Lower solute concentration outside cell Plant Cell
Isotonic Solution The concentration of solutes is equal inside and outside the cell so water moves across the membrane in both directions maintaining cell size Animal Cell Plant Cell Equal solute concentration inside and outside cell
Hypertonic Solution The solution has a higher solute concentration than the cell so water moves out of the cell and into the solution causing the cell to plasmolyze Animal Cell Plant Cell higher solute concentration outside cell
Facilitated Diffusion A) Substance specific protein channels allow movement of molecules such as glucose to move across the membrane in either direction B) Substances still move high concentration to low concentration and no energy is required
Active Transport Characteristics: – Movement of substances is against the concentration gradient – Energy is required ! Types of Active Transport – Molecular transport – Endocytosis – Exocytosis REMEMBER: Requires ATP Energy!
Active Transport – Molecular Transport Molecular transport: Protein molecules act like energy requiring pumps to move molecules and ions across membranes
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Active Transport – Endocytosis Endocytosis – Materials are taken into the cell by means of forming in the cell membrane. The pocket becomes a vacuole inside the cell.
Cool video showing Endocytosis s Paramecium EATS 2 amoebas k&feature=fvwrel
Exocytosis – EXPEL WASTES FROM CELL Wastes moved out of the cell when a vacuole fuses with the cell membrane Active Transport – Exocytosis