Membrane Transport
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What is the definition of a Concentration gradients?
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It is the difference in concentration of a molecule across a membrane
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What is simple diffusion?
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movement of small uncharged molecules through lipid bilayer
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What molecules can readily exchange between the membrane?
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O2 and CO2
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What is Facilitated diffusion?
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The protein provides a water soluble passageway through the lipid bilayer. An ion channel is a good example
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What is osmosis?
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Semi-permeable membrane. Permeable to water but not solute (sugar). Equilibrium reached when concentration is H20 equal on both sides.
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In what direction does water move during osmosis?
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water moves from compartment of low solute concentration to compartment of high solute concentration
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What is the difference between hypertonic, hypotonic, and isotonic solutions?
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1. hypertonic solution - solute concentration greater outside cell 2. hypotonic solution - solute concentration less outside cell 3. isotonic solution - solute concentration same inside and out
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What is active transport?
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required to move molecules against a concentration gradient (requires ATP)
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What is uniport transport?
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Single substance is moved in single direction
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What is Antiport transport?
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Movement of two molecules in opposite directions and requires energy (ATP).
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What is Symport transport?
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movement of two molecules in same direction
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What is Diffusion?
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Molecules and ions tend to move down a concentration gradient (High to low concentration)
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Higher Temperature =
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Greater diffusion rates
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What is Tonicity?
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The amount of solute per volume solution
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What is Osmotic Pressure?
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force required to counteract the movement of water
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Exocytosis
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Substances are directed out of a cell to be secreted
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Endocytosis
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Substances are engulfed into a cell
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What is the difference between primary and secondary active transport?
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In secondary transport, the transporter molecule does not require ATP directly
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What is passive transport?
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Does not require ATP, Examples: Facilitated diffusion, simple diffusion, and ion channels.
