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31 Cards in this Set
- Front
- Back
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diffusion
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movement from high to low concentration down a concentration gradient; NO ENERGY --> PASSIVE
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what factors influence diffusion?
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temperature, mass of molecule, surface area, the medium of transport (more rapid in gas)
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what is fick's first law?
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the rate of diffusion is proportional to surface area and the difference in concentration
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what are ligand gated channels
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regulated by the presence of certain chemicals
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what are stretch/mechanosensitive channels?
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regulated by the stretch of the membrane
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what are voltage gated channels
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regulated by the electrical charge across the membrane
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what is mediated transport?
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a membrane protein catches large molecules in extracellular fluid and transfers them across the membrane into the cell
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what are transporters?
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proteins involved in mediated transport
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what are factors that affect rate of mediated transport?
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relative affinity, how many transporters, how fast the transporter works
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list the types of facilitated diffusion.
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facilitated diffusion, active transport, vesicular transport
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what is facilitated diffusion?
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mediated transport that is solely driven by the diffusion gradient
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what is active transport?
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uses energy to drive the transport process; allows molecules to move against concentration gradient;
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what is primary active transport?
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the hydrolysis of ATP is involved directly
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what is secondary active transport?
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transport is driven by a ion concentration gradient, set up primary active transport
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what is the transporter in primary active transport?
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ATP-ase (ex: NA,K-atase,CA-atpase,H-atpase,K-atpase)
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what is the mM of K using the Na,K-atpase
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150mM out vs. 4mM out
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what is mM of Na using NA,K-atpase?
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15mM vs. 145 out
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For each ATP how much Na and K is used in Na,K-atpase
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3 Na out, 2 K in
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what is co-transport
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same direction as the ion is driivng the transport
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what is counter transport
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transfer is in opposite direction
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what is uniport?
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transport in one direction
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what is symport?
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2 molecules are transported in same direction by the same transporter
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what is antiport?
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2 molecules transported in opposite directions by the same ransporter
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how much of body weight is water?
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60% --> in 70kg man about 42L
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what forms water channels?
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aquaporins
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what is osmosis?
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water moving down its concentration gradient
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what is osmolarity?
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concentration of water; total solute concentration in it; 1 osmole = 1 mole of solute; higher osmolarity is lower water concentration
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what is nomarl physiological osmolarity?
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290 miliosmolar
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what is osmotic pressure?
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pressure that must be applied to counteract the osmotic flow of water
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< 300 mOsm
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hypotonic; water will diffuse from that solution into a physiologically normal solution (300)
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>300
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can't know tonicity until we know whether the solute will permeate through the membrane; putting cell in a hypertonic solution will cause it to shrink (fluid inside the cell is hypotonic relative to fluid outside)
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