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HOMEOSTASIS
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Discussion Questions 1. What is homeostasis? 2. What does a living thing need to perform homeostasis? 3. What are some examples of things that the body will regulate?
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4. What are some examples of how the body regulates these things? 5. How does the body do homeostasis?
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Homeostasis in the Human Body homeostasis
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An example of homeostasis within the human body: DIALYSIS It’s a process that separates solvents from blood. Such as removing glucose or fats with out removing the important molecules that our blood needs. The tubing used in semi-permeable. Meaning some material can pass through and others cannot.
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The Cell Membrane
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Label your cell membrane!
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A membrane is a device that selectively permits the separation of one or more materials from a liquid or gas. What is a membrane? ?
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Diffusion Demonstration Model Molecules are always in motion In a closed system the molecules evenly try to distribute Which results in a the initial movement of molecules from high to low concentrations Once an equilibrium is reached there is no net movement of molecule.
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What is separating the two different types of beads? How do the two volumes compare in this model? Which side of the model has a higher concentration of beads? How is diffusion going to take place? What happens with continued shaking? Is equilibrium reached? (Has homeostasis been reached?)
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Passive Transport The transport of substances through the cell membrane without using energy.
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Diffusion The process of moving from areas of high concentration to areas of low concentration
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Osmosis
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Osmosis The diffusion of water from areas of high concentration to areas of low concentration through a semi- permeable membrane.
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Osmosis Cont. The concentration (amount) of all substances affects the movement of materials in and out of the cell.
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Explain to your lab partner why water is moving into the cell…
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SUMMARY: Water moves from a high concentration of water (less salt or sugar dissolved in it) to a low concentration of water (more salt or sugar dissolved in it). This means that water would cross a selectively permeable membrane from a dilute solution (less dissolved in it) to a concentrated solution (more dissolved in it).
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Water can cross the cell membrane through the lipid bi-layer and with special proteins. If enough water enters the cell by osmosis, the cell can swell enough to burst open and die. This is demonstrated in the picture.
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Hypotonic Solute concentration: contains a low concentration of solute Water concentration: contains a high concentration of water Water movement: water diffuses into the cell Effect on the cell: causing the cell to swell and possible explode
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Exploding RBC Exploding RBC
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Cells in hypotonic solution
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Draw a picture
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Isotonic Solute concentration: is equal to the water concentration Water concentration: is equal to the solute concentration Water movement: equal diffusion (water diffuses into and out of the cell at equal rate) Effect on cell: none
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Normal cells in isotonic solution
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Draw a picture of an isotonic solution next to the definition
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Hypertonic Solute concentration: contains a high concentration of solute Water concentration: contains a low concentration of water Water movement: water diffuses out of the cell Effect on the cell: causing the cell to shrivel
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Cells in hypertonic solution RBC's shrinking! RBC's shrinking!
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Draw a picture next to the definition
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Quiz yourself 1 23 1 23
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Watch video after you conduct the potato lab! Egg Experiment Egg Experiment
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Active transport
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The transport of molecules from areas of high to low concentration with the use of energy. The cells energy is the ATP made in the mitochondria.
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Bulk movement of substances across the membrane Endocytosis: Phagocytosis Pinocytosis Exocytosis
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Endocytosis A process by which a cell surrounds and takes in materials from its environment by engulfing them.
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Phagocytosis “CELL EATING”. Process in which phagocytes engulf and digest microorganisms and cellular debris "phagocyte" or eating cell "phagocyte" or eating cell (phago = "eating", cyte = "cell"). An important defense against infection
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phagocytosis
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Pinocytosis “CELL DRINKING”. Process by which certain cells can engulf and incorporate droplets of fluid
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Examples on Endocytosis Is it phago or pino… Is it phago or pino…
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Exocytosis when materials and wastes are transported out of the cell.
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Label where endo and exo take place
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Diffusion Quiz Diffusion Quiz
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Bookwork Facilitated Diffusion:
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