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72 Cards in this Set
- Front
- Back
Regulates passage of materials into and out of cell
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Cell membrane
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How thick is the cell membrane
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7-9 nanometers thick
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What is a cell membrane composed of
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Phospholipid bilayer
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Where are glycolipids usually found on the cell membrane
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Outer surface
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Glycoprotein -------> _____ & ____
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Carbs and proteins
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Proteins within the membrane are called ____
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Integral proteins
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Proteins on the cytoplasmic side are called ________
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Peripheral proteins
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Replaced Davson - Danielli's "Sandwich Model" of the cell membrane
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Fluid Mosaic Model
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No energy needed; movement of materials across the cell membrane
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Passive transport
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Type of passive transport; high to low with concentration. Net movement of a substance down a concentration gradient
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Diffusion
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Controls the rate of passive transport
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Temperature, concentration, and pressure
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Movement of water molecules across a membrane
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Osmosis
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High solution concentration in solution - H2O goes out of cell and the cell becomes flaccid (limp)
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Hypertonic
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Equal solution concentration and water in both solutions. Reached equilibrium
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Isotonic
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Low solute concentration in solution. H2O goes into cell. Increase in turgor pressure in plant cells, is Turgid
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Hypotonic
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Why does water move from one place to another?
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Difference in potential energy
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In what way does water move
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From a region where water potential is greater to a region where water potential is lower
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What affects the movement of water and solutes
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Gravity, pressure, and concentration of dissolved substances (solutes)
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The ____ the concentration of water molecules the greater the water potential
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Higher
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Water potential is measured in terms of the ____ required to stop to movement of water
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Pressure
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Water movement from one place to another because of differences in potential energy
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Water potential
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Tendency of water to move across a membrane into a solution
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Osmotic Potential
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Osmotic potential of pure water is
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0
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Osmotic potential of water and solution is
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< 0
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The lower the water potential of a solution the ____ the tendency of water molecules to move into it by osmosis, and therefore the greater the osmotic potential
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Greater
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Because solutes decrease the water potential of a solution, a ___ solute concentration means a greater osmotic potential
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Higher
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High water ----> ____ osmotic potential
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Low
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High osmotic potential ------> ____ water
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Low
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Total solute concentration of a solution
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Osmotic concentration
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Measure of tendency of a solution to take up water when separated from pure water by a selectively permeable membrane
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Osmotic pressure
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Osmotic pressure of pure water is
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0
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Greater the osmotic pressure, ____ the solute concentration
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Greater
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Device to measure osmotic pressure
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Osmometer
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Cell membrane pulls away from cell wall as water moves out
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Plasmolysis
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Shrinking of cell due to water loss (shrivel)
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Crenation
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Bursting due to taking too much water into cell
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Cytolysis
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Regulation of water balance by organisms in a hypo or hyper environment
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Osmoregulation
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How does water move in osmosis (water potential)
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From a region of high water potential to a region of low water potential
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How does water move in osmosis (water concentration)
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From high water concentration to lower water concentration
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How does water move in osmosis (solute concentration)
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From low solute concentration to higher solute concentration
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How does water move in osmosis (Hypotonic solution)
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From Hypotonic solution to hypertonic solution
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Hows does water move in osmosis (Osmotic potential)
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From a region of low osmotic potential to a region of high osmotic potential
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What drives facilitated diffusion
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The potential energy of the concentration gradient
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What helps facilitated diffusion
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Transport proteins
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Open only in response to electrical or chemical stimuli
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Gated or selective channels
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A transport protein that generates voltage across a membrane
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Electrogenic pump
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Major electrogenic pump in plants
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Proton pump
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Mitochondria and chloroplasts use a proton pump to drive _____ ____
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ATP synthesis
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Voltages created by electrogenic pumps are sources of _____ ____ that are available to do ___ ____
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Potential energy :: Cellular work
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Process where a single ATP powered pump actively transports one solute and indirectly drives the transport of other solutes against their concentration gradients
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Cotransport
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Transport Proteins are (Hydrophilic/Hydrophobic)
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Hydrophilic
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Three major types of Transport Proteins
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Uniport, Symport, Antiport
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Type of Transport protein - Moves only 1 molecule across in one direction
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Uniport
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Type of Transport protein - Moves 2 molecules across in the same direction at the same time
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Symport
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Type of Transport protein - Moves 2 different solutes in opposite directions
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Antiport
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Two ways small molecules cross membranes :
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1) Passing through the phospholipid bilayer
2) Being translocated by a transport protein |
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Large molecules cross membranes by the mechanism of : (2 ways)
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1) Exocytosis
2) Endocytosis |
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Process where a cell secretes macromolecules by fusion of vesicles with the plasma membrane
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Exocytosis
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Cell "Dumping"
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Exocytosis
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Vesicle usually budded from the ER/Golgi and migrates to plasma membrane
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Exocytosis
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Used by secretory cells to export products
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Exocytosis
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Process where a cell takes in macromolecules by forming vesicles derived from the plasma membrane
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Endocytosis
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Vesicle sinks inward and pinches off into the cytoplasm
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Endocytosis
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Cell "Eating"
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Endocytosis
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The two types of Endocytosis are
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1) Phagocytosis
2) Pinocytosis |
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Cell eating; solid, larger particles engulfed and forms a food vacuole which fuses with a lysosome to digest with hydrolytic enzymes
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Phagocytosis
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Cell drinking; taking in extracellular liquid droplets into small vesicles. The cell takes in any and all solutes with liquid
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Pinocytosis
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More discriminating that pinocytosis
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Receptor mediated endocytosis
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In receptor mediated endocytosis, coated pits form vesicles when specific ____ bind to receptor sites on the cell membrane
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Ligands
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The molecule that binds to the specific receptor site
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Ligands
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In receptor mediated endocytosis, a layer of ___, a ribrous protein, liens and reinforces the coated pit on the cytoplasmic side
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Clathrin
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Enables cells to acquire bulk quantities of specific substances even if they are in low concentration in the extracellular fluid
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Receptor mediated endocytosis
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