CAIE A Level Biology 9700 · Control and coordination
The table below shows the changes in membrane potential of a neurone during a single action potential.
| Time / ms | Membrane potential / mV |
|---|---|
| 0.0 | -70 |
| 0.5 | -70 |
| 1.0 | -55 |
| 1.5 | +30 |
| 2.0 | +10 |
| 2.5 | -20 |
| 3.0 | -50 |
| 3.5 | -70 |
| 4.0 | -75 |
| 4.5 | -70 |
| 5.0 | -70 |
Describe the sequence of events that produce these changes in membrane potential.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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