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Edexcel A-Level Biology A2 8.4 Action Potential Conduction Questions

Start at resting potential, trace depolarisation and repolarisation with channel direction and use graph coordinates or concentration data in the requested comparison.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
A2

Exam points

  • Explain depolarisation and repolarisation through sodium and potassium ion movement.
  • Interpret membrane-potential graphs to identify resting potential and hyperpolarisation.
  • Calculate potential differences or compare conduction speed from temperature and ion data.

Edexcel A-Level Biology A2 8.4 Action Potential Conduction Questions question 1

[Maximum number: 7]

Many predatory animals produce toxins to disable their prey. Some of these toxins inhibit nervous communication.

Question (a)

(a)

Describe the role of ion transport in maintaining the resting potential of a neurone.

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Question (b)

(b)

The pufferfish produces a neurotoxin called tetrodotoxin (TTX).

The graph shows the effect of TTX on the nerve impulse in an axon.

Membrane voltage / mV

Deduce how TTX inhibits nerve impulses in an axon.

Figure for Question (b) — Edexcel A-Level Biology A2
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