Biology 9700 · AS & A Level · Control and coordination in mammals
Control and coordination in mammals — practice question
Voltage-gated channels take part in the formation of an action potential. Fig. 9.1 shows the voltage-gated sodium ion and potassium ion channels in the membrane of an axon. These channels are illustrated in three separate states, 1, 2 and 3. Fig. 9.2 shows the different stages of an action potential in an axon. The stages are labelled A, B, C, D, E, F and G.
(a)[3]
Fill in Table 9.1 by linking each of the listed phases of the action potential to the correct voltage-gated channel state: 1, 2 or 3.
(b)[3]
Many neurones are enclosed by myelin sheaths. Describe and explain the function of the myelin sheath in the transmission of an action potential.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “accurate pairing of action potential phases with channel states” …