Biology 9700 · AS & A Level · Control and coordination in mammals
Control and coordination in mammals — practice question
As an action potential develops, the potential difference across a neurone membrane alters. Table 10.1 gives the potential difference across the neurone membrane at three successive time points X, Y and Z, immediately before and during an action potential.
(a)[7]
Describe the events responsible for each of the potential differences at points X, Y and Z.
(b)[2]
Suggest how one action potential triggers an action potential in an adjacent section of the axon of an unmyelinated neurone.
(c)[3]
Vertebrate animals usually have a myelin sheath around the axons of motor neurones. Explain why having a myelin sheath around a motor neurone axon is advantageous.
Worked solution & mark scheme
This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “sodium-potassium pump sets up $-70\,\text{mV}$” …