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15 Cards in this Set
- Front
- Back
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What does the kinetic behavior of a channel refer to? |
the durations of the closed and open states (p. 70) |
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What does the channel current refer to? |
It's a direct measure of how rapidly ions move through channel. (p. 70) |
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The current depends on channel properties as well as... |
transmembrane potential (p.70) |
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During use of patch clamp recording, what can you use to prevent the loss of important cytoplasmic components? |
a perforated patch (p. 69) |
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Channels can display complicated kinetics such as channel openings that occur in... |
bursts (p. 69) |
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What are two advantages of using patch clamp techniques for studying channel behavior? |
Isolation of a small patch of membrane allows us to observe a few channels at a time, and the high resistance of the seal enables us to record extremely small currents. (p. 69-70) |
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What is being measured by the microelectrode? |
Changes in potential from channel activation (Figure 4.3 and 4.4) |
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When Acetylcholine is applied to a muscle at rest what happens across the membrane? |
There are relatively large fluctuations (noise), due to random openings and closings of ACh-activated channels (Figure 4.3 and 4.4) |
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What is the function of an oscilloscope? |
To show the amplitudes and durations of single channel currents (Figure 4.3 and 4.4) |
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Katz and Miledi performed experiments on frog muscle fibers to examine the characteristics of noise produced by_____ at the neuromuscular junction. |
Acetylcholine (p. 67) |
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The first experiments designed to examine the properties of membrane potential used what instrument? |
glass microelectrode (p. 67) |
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In performing an intracellular recording experiment, a successful penetration of cytoplasm is indicated by the appearance of ____ of the cell. |
resting potential (p. 67) |
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What is noise analysis? |
Analysis of fluctuations in membrane potential or current due to random opening and closing of ion channels (p. 68) |
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What is patch clamp recording? |
A technique in which a small patch of membrane is sealed to the top of a micropipette and currents though single-membrane channels are recorded (p. 68) |
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What is whole-cell patch recording? |
Recording of membrane current of an intact cell with a patch clamp electrode through an opening made in the cell membrane (p. 68) |
