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Cellular Transport Objectives. By the end of this lesson you should be able to… Describe the structure and function of the cell membrane. Compare and contrast passive and active transport. Compare and contrast the three types of passive transport.
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Cellular Transport Objectives By the end of this lesson you should be able to… • Describe the structure and function of the cell membrane. • Compare and contrast passive and active transport. • Compare and contrast the three types of passive transport. • Explain what would happen to a cell if it were placed in a hypertonic, hypotonic, or isotonic solution.
Cellular Transport The movement of nutrients, good gases, and water into the cell and waste products out of the cell through the cell membrane.
Cell Membrane’s Function • Provide protection and support for the cell. • Maintain Homeostasis
Cell Membrane • Semi or selectively permeable • Controls what enters and exits cell • Made of phospholipid bilayer • Contains proteins involved in transport
Cellular Transport Two Types Active Transport Passive Transport Requires ENERGY from the cell Does NOT require energy from the cell Moves against the concentration gradient from low to high Requires a concentration gradient moving from high tolow
Possible questions and underlined key words • Cellular Transport • What is the difference between passive and active transport? • Compare passive and active transport to the movement of a sled down a hill and up a hill. • Cell Membrane • What is the function of the cell membrane? • How does the cell membrane control homeostasis? • What is the structure of the cell membrane?
Examples of Passive Transport • Three types of passive Transport • Diffusion • Facilitated Diffusion • Osmosis
Diffusion • Requires no cell energy • Particles move from areas of high concentration to areas of low concentration • Examples • Aroma of fresh baked cookies • Oxygen and Carbon dioxide exchange in lungs
Facilitated Diffusion • Requires no cell energy • Particles move from high concentration to low concentration • Particles move across membrane through channel proteins in membrane
Osmosis • Requires no cell energy • Movement of water across a selectively permeable membrane • Water molecules move down concentration gradient
What controls Osmosis • Water moves across selectively permeable membrane in response to solute concentration • Water molecules are trying to reach equilibrium • Therefore solutions across membranes will have different solute concentrations
Solute-material dissolved in solution • Solvent-material that does the dissolving • Solution-mixture of the two
Different Solution Types • Hypotonic solution • The solute concentration outside the cell is lower than the solute concentration inside the cell
Hypotonic Solution • Red Blood Cell in distilled water will move into the cell and lyse or pop it. • Water moves into plants and is stored in the vacuole pushing the cell membrane up tight to the cell wall. The cell wall will keep it from popping.
Hypotonic Solutions • Protists which live in fresh water have contractile vacuoles that pump water out. It looks like a sunshine.
Different Solution Types • Hypertonic solution • solute concentration outside of the cell is higher than the solute concentration inside the cell.
Hypertonic Solution • Red Blood Cell in salt water will cause the cell to shrink or dehydrate • Plant cell in a hypertonic solution will experience plasmolysis, or the cell membrane shrinking away from the cell wall because the vacuole is empty.
Different Solution Types • Isotonic solution • solute concentration outside of the cell is equal to the solute concentration inside the cell.
Examples of Active Transport • Endocytosis-process in which cell takes in particles by surrounding them • Phagocytosis • Pinocytosis • Exocytosis-process in which cell expels particles by using vessicles that attach to and open the cell membrane.
