IB Biology SL C2.2 Neural Signalling Questions

Practise IB Biology SL C2.2 by linking neuron structure, resting potential, myelin and impulse conduction to exam evidence.

Exam points

explain resting potential using sodium-potassium pumps and ion movement across axon membranes
link myelin, nodes of Ranvier and axon diameter to faster impulse conduction
interpret a basic action-potential trace by identifying depolarisation, repolarisation and refractory phases

Covered syllabus points

C2.2.1—Neurons C2.2.2—Resting potential generation C2.2.3—Nerve impulses as action potentials C2.2.4—Variation in impulse speed C2.2.5—Synapses as junctions C2.2.6—Neurotransmitter release C2.2.7—Excitatory postsynaptic potential

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Study C2.2 Neural signalling conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

[Maximum number: 6]

The diagram below shows a motor neuron.

(a)

Label the structures indicated by the numbers I-IV.

[ 2 ]

(b)

Define resting potential.

[ 1 ]

(c)

Outline how nerve impulses are transmitted along a nerve fibre.

[ 3 ]

a. (sodium channels/voltage-gated channels open and) $\mathrm{Na}^{+}$ diffuse into neuron (down concentration gradient);
b. inside of neuron becomes positive compared to outside / potential is reversed / depolarization;
c. wave of depolarization moves (down the membrane);
d. (potassium channels open and) $\mathrm{K}^{+}$ diffuse out (down concentration gradient);
e. inside becomes negative compared with outside / potential across membrane restored / repolarization;
f. active transport of $\mathrm{K}^{+}$ (into neuron) and $\mathrm{Na}^{+}$ (out of neuron) restores resting potential;

All question bank results loaded

I	nucleus/cell body/soma
II	myelin sheath/Schwann cell
III	axon
IV	dendrites

Covered syllabus points

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Question 1

Question (a)

Question (b)

Question (c)