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29 Cards in this Set
- Front
- Back
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Cell Wall |
- A stiff covering around the cell membrane of certain cells - Composed of Carbohydrates and proteins - stability, hold shape, prevents lysis and retains water - plants (cellulose), fungi (chitin), most algae, some bacteria (peptidoglycan) |
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Cell Membrane |
- a selectively permeable barrier separated the interior of the cell from the outside environment - allows materials to pas through interact w the extracellular environment -separate chemical reactions - composed of lipid bilayer - glycolipids and proteins act as antennae to get messages |
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selectively permeable |
- barrier that regulates the exchange of molecules between the interior of cell and the environment |
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what crosses the membrane? |
-materials needed to perform cell functions water, ions, carbs, proteins, hormones , waste |
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Transport Proteins |
- an organic molecule that assists the active or passive movement of materials through the cell membrane |
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Diffusion |
- movement of molecules from a higher concentration area to a low concentration area ex: perfume molecules spread out to atmosphere |
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why does gas work better than a water based liquid? |
the gases move in air and they will diffuse quicker |
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What happens when there is a greater number of molecules in a higher concentration area? |
- molecules move randomly collide/move - more likely the molecules will move toward a lower concentration area without colliding. |
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Does entropy increase or decrease during diffusion? |
- increases as the system becomes more disorganized. |
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equilibrium |
- molecules continue to move yet there are no area of higher, lower concentration - something is equally distributed - molecules are still moving randomly in random directions - balance |
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concentration gradient |
- a difference in concentration of molecules across a distance |
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what does going against concentration gradient use? |
ENERGY!!!! |
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creates potential energy and electric potential gradients across a membrane |
selectively permeable membrane |
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nerve impulses |
rely on gradients of ionic substances |
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factors that affect diffusion rates |
- steeper gradient: if there is a larger difference of molecules across same distance then mol. will move faster down conc. gradient because trying to reach equilibrium - surface area: sum of all the areas of the shapes that cover the surface of object
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Osmosis |
-movement of water down conc. gradient - DOESN'T REQUIRE ANY ENERGY - passive transport system |
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Three Tensities |
- Hypertonic, hypotonic, isotonic |
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hypertonic |
- large solute conc. OUTSIDE the cell, water exits the cell to balance solution |
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Hypotonic |
- large solute concentration INSIDE the cell and water enters the cell membrane to balance solution - if too extreme cell may burst |
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Isotonic |
- equal/balanced concentration inside and outside the cell |
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Turgor |
- outward pressure of cell against cell wall |
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what factors will affect conc. gradient |
surface area, concentration of X |
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Passive Transport |
- no energy is needed for molecules to move across membrane |
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facilitated diffusion
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- type of passive transport - molecules move down concentration gradient assisted by transport (transport/carrier proteins) |
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Active Transport |
- energy is needed for molecules to move independent of gradient (down or against) |
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endocytosis |
- cellular uptake of materials in which the plasma membrane surrounds and engulfs extra cellular materials - phagocytosis and pinocytosis |
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phagocytosis |
- type of endocytosis - engulfs SOLIDS |
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pinocytosis |
- engulfs small materials - engulf small materials |
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exocytosis |
- release of macromolecules from a cell by the fusion of vesicles with the plasma membrane |
