Term
| What does the direction of current on a read-out from channel recordings indicate? |
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Definition
| current is the direction of positive charge movement on channel recording readouts (readouts = trace feed) |
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Term
| What does a flat line on a read-out from a channel recording indicate? |
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Definition
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Term
| Is the duration of channel openings constant? |
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Definition
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Term
| the classic view of diffusion |
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Definition
| everything moves from areas of high concentration to areas of low concentration --> balanced concentration |
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Term
| describe how molecules move in the establishment of equilibrium |
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Definition
| not a straight line from all molecules on one side to half of them being on the other side; sometimes molecule movements overshoot equilibrium; molecule movement is random; molecules never stop moving |
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Term
| What happens with every conformation change of the sodium-potassium pump? |
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Definition
| 3 sodium pumped out & 2 potassium pumped in |
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Term
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Definition
| generates electricity which contributes to your membrane potential |
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Term
| Are sodium-potassium pumps relatively fast or relatively slow? |
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Definition
| relatively slow (compared to ion channels) |
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Term
| The sodium-potassium pump contributes to resting membrane potential in the ______ direction |
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Definition
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Term
| 3 parts of the structure of the sodium-potassium pump |
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Definition
1. alpha subunit with 10 TMR
2. beta subunit
3. relatively small gamma subunit (1 transmembrane alpha helix) |
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Term
| difference between the extracellular & intracellular binding sites on the sodium-potassium pump |
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Definition
extracellular binding site for potassium
intracellular binding site for sodium |
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Term
| Where is the binding site for ATP on the sodium-potassium pump? |
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Definition
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Term
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Definition
| recover ions that cross the membrane & move ions against electrochemical gradients |
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Term
| Does ion transport across cell membranes require energy? |
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Definition
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Term
| 2 types of transport mechanisms based on energy source |
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Definition
1. primary active transport (uses ATP)
2. secondary active transport (uses concentration gradients) |
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Term
| 10 steps of the sodium-potassium ATPase pump |
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Definition
1. sodium binds intracellularly
2. ATP binds intracellularly & is hydrolyzed
3. ATPase is phosphorylated
4. conformational change
5. sodium sites are extracellular
6. sodium is released
7. potassium binds extracellularly
8. phosphate group is released from pump
9. conformation change
10. potassium is released intracellularly |
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Term
| The sodium-potassium ATPase pump transports ______ out for every _____ in |
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Definition
| 3 sodium ions out for every 2 potassium ions in |
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Term
| _____ is the only ion that can be transported out of the cell by sodium-potassium ATPase |
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Definition
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Term
| Is external potassium required for the sodium-potassium ATPase pump to function? |
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Definition
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Term
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Definition
| blocks the sodium-potassium ATPase pump (form the French "ouabaio" for "arrow poison") |
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Term
| short term effects of Ouabain |
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Definition
| very small but abrupt depolarization of the membrane |
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Term
| long term effects of Ouabain |
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Definition
| membrane potential continues to go up but more slowly than the initial depolarization (approaching 0 mV) |
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