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Notes 5.1 Osmosis in Action. Pages 99-100. Table Talk. Watch this video . As a group discuss the answers to these questions: What organism is this? What kind of environment do you think it’s in? What is happening?. Standards.
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Notes 5.1Osmosis in Action Pages 99-100
Table Talk • Watch this video. • As a group discuss the answers to these questions: • What organism is this? • What kind of environment do you think it’s in? • What is happening?
Standards • CLE 3210.1.5 - Compare different models to explain the movement of materials into and out of the cell. • SPI 3210.1.8 - Compare active and passive transport. • RLE 2010.2.1 - Recognize the importance of homeostasis as a survival mechanism.
Objectives • Compare different models to explain the movement of materials into and out of the cell and the role of the solution the cells exist within. • Diffusion • Facilitated diffusion • osmosis • Recognize the importance of homeostasis as a survival mechanism.
Quick Review • Solutions have: • Solvent: • Solute(s): • Concentration: • Osmosis: The liquid that dissolves the solute. The substance that gets dissolved. the amount of a substance in a given volume When water moves from high to low concentration.
So What? • Cells live in solutions…. So we’ve named the three types of solutions: • Isotonic • Hypertonic • Hypotonic
Isotonic • Isotonic: • What happens: Concentrations of solutes are the same inside and outside of the cell. Water is at an equilibrium so it moves freely into and out of the cell at the same rate.
Hypertonic • Hypertonic • What happens? Concentrations of solutes are higher outside the cell than inside. Water moves outside the cell in order to create a dynamic equilibrium. Cells shrivel up and may die (in plants it’s called plasmolysis.)
Hypotonic Hypotonic: What happens: Concentrations of solutes are lower outside the cell than inside. Water moves into the cell in order to create a dynamic equilibrium. Cells expand and may explode (called cytolysis.)
Summary Good graphic on page 99.
Review • Watch this videoagain. • As a group discuss the answers to these questions: • What organism is this? • What kind of environment do you think it’s in? • What is happening?
Quick Review Equal • Isotonic – solutes are __________ within the solution in comparison to the cell • Hypertonic – solutes are __________ within the solution in comparison to the cell • Hypotonic – solutes are ___________ within the solution in comparison to the cell Higher Lower
Objectives • Compare different models to explain the movement of materials into and out of the cell and the role of the solution the cells exist within. • Diffusion • Facilitated diffusion • osmosis • Recognize the importance of homeostasis as a survival mechanism.
Cell Responses to Osmosis Land Organisms: Saltwater Organisms: Freshwater organisms: Cells inside our bodies are in slightly hypotonic environments. No problems under normal conditions. Live in a hypotonic environment.
Hypotonic Environment Defenses Single-cell organisms: Contractile Vacuole: Multi-celled organisms: Solute Pumps: a sac that stores water and when it is full the sac contracts and the water is expelled. (If it fails the paramecium will die.) Proteins in the cell membrane can pump solutes out of the cell, making the concentrations of water more equal.
Plant Cells Hypotonic Environments: Turgor Pressure Hypertonic Environments: Plasmolysis As the plant cell swells, the pressure of the water is not enough to break the cell wall. This gives soft plants rigidity. As plant cells lose water, the cell membrane pulls away from the cell wall and turgor pressure is lost and the plant wilts.
No Defenses Some cells have no defense against osmosis. Example: Red Blood Cells - hypotonic Red Blood Cells - hypertonic
Review • Watch this videoagain. • As a group discuss the answers to these questions: • What organism is this? • What kind of environment do you think it’s in? • What is happening?
Review the Objectives • Compare different models to explain the movement of materials into and out of the cell and the role of the solution the cells exist within. • Diffusion • Facilitated diffusion • osmosis • Recognize the importance of homeostasis as a survival mechanism.