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14 Cards in this Set
- Front
- Back
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The ________ _______ model helps explain how membranes regulate the cell's molecular traffic.
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fluid mosaic
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True or False: A steady traffic of small moelcules and ions move across the plasma membrane in only one direction.
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False. They move in both directions.
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True or False: The cell regulates its concentrations of inorganic ions, such as Na+, K+ etc
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True. It shuttles them one way or the other across the plasma membrane.
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True or False: Things that pass through the membrane does so as the same rate as any other substance.
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False. They all move at their own rate.
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Do nonpolar molecules need the help of membrane protein to cross the lipid bilayer?
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no because they are hydrophobic and can dissolve easily to cross.
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Do polar molecules cross the lipid bilayer quickly or slowly?
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Slowly.
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How do hydrophilic substances cross the lipid bilayer?
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Through transport proteins
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What is a nother name for transport proteins?
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channel proteins
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What enables transport proteins to channel other hydrophilic substances through the lipid bilayer?
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they have a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane.
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What is an aquaporin?
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An aquaporin is a type of channel protein that allows the passage of water molecules
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What do carrier proteins do?
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they hold onto their passengers and change shape in a way that shuttles them across the membrane.
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True or False: A transport protein allows any type of substance to pass through one channel protein.
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False. A transport protein is specific for the substance is translocates, allowing only a certain substance or substances to cross the membrane.
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Two molecules that can cross a lipid bilayer without help from membrane proteins are O2 and CO2. What properties allow this to occur?
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they're hydrophobic or non polar
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Why would water molecules need a transport protein to move rapidly and in large quantities across a membrane?
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Because it is polar/hydrophilic and would repel against the hydrophobic part of the lipid bilayer.
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