Syllabus Edition
First teaching 2014
Last exams 2024
1 markBetween which structures do sensory neurones transmit electrical impulses?
From effectors to the central nervous system (CNS).
From effectors to receptors.
From receptors to effectors.
From receptors to the central nervous system (CNS).
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1 markWhere would myelin be found?
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1 markWhich event directly results in the production of an action potential?
Diffusion of neurotransmitter across the synaptic cleft.
Fusion of vesicles with the presynaptic membrane.
Membrane potential reaches the resting potential.
Membrane potential reaches the threshold potential.
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1 markIdentify where depolarisation is occurring.
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1 markNeurotransmitters leave the presynaptic neurone and enter the synaptic cleft. After this, they travel across the cleft to a receptor on the postsynaptic neurone membrane.
Identify the processes that are required for this to occur.
| Neurotransmitters enter synaptic cleft | Neurotransmitters travel across cleft | |
| A. | Endocytosis | Diffusion |
| B. | Endocytosis | Active transport |
| C. | Exocytosis | Diffusion |
| D. | Exocytosis | Active transport |
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1 markNeonicotinoids are synthetic compounds similar to nicotine that are commonly found in pesticides. Neonicotinoids are considered to be especially suitable as pesticides because they're not toxic to humans and other mammals.
Which statements I - IV are the reasons for this?
I. A larger proportion of synapses in insects are cholinergic compared to mammals.
II. Neonicotinoids are more effective at preventing acetylcholinesterase from breaking down acetylcholine in insects compared to mammals.
III. Acetylcholinesterase in insects cannot break down neonicotinoids.
IV. Neonicotinoids bind more strongly to acetylcholine receptors in insects.
I and IV
I, II and IV
II and III
II only
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1 markThe diagram below shows the left to right transmission of an action potential in a myelinated axon by saltatory conduction.
Which of the following rows correctly identifies I - IV?
| I | II | III | IV | |
| A. | Node at resting potential | Node at action potential | Node at refractory period | Node becoming depolarised |
| B. | Node at refractory period | Node at action potential | Node becoming depolarised | Node at resting potential |
| C. | Node at action potential | Node at refractory period | Node becoming depolarised | Node at resting potential |
| D. | Node at refractory period | Node becoming depolarised | Node at action potential | Node at resting potential |
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1 markThe oscilloscope trace shown below was taken using a digital oscilloscope. It shows an action potential in a hippocampal pyramidal neurone of a potoroo (a small marsupial species) that occurred when the neurone was stimulated with a current pulse.
How many action potentials could be stimulated in this neurone every second?
6
60
12
7
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1 markA research group of geneticists found a fruit fly mutant that shakes vigorously when anaesthetized with ether. Their studies showed that the shaker mutant has K+ channels that do not function properly. An action potential of a normal fruit fly and a shaker mutant is shown below.
Which of the following statements (I - IV) could be possible explanations for the differences between the action potentials?
I. The faulty K+ channels don't open for as long so there is slower diffusion of K+ ions.
II. The faulty K+ channels may be opening early, preventing maximum depolarisation.
III. The faulty K+ channels cause K+ ions to diffuse back into the axon more slowly, resulting in slower repolarisation.
IV. In wild-type drosophila, the functioning K+ channels allow for a faster rate of depolarisation.
I only
II and III
I, II and IV
I and II
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1 markStudy the diagram below.
Which of the following table rows correctly identifies I - VI?
| I | II | III | IV | V | VI | |
| A. | Acetylcholine | Acetyl-cholinesterase | Cholinergic receptor | Choline | Acetyl group | Acetyl-CoA |
| B. | Acetyl-cholinesterase | Acetyl-CoA | Acetylcholine | Cholinergic receptor | Choline | Acetyl group |
| C. | Acetylcholine | Cholinergic receptor | Acetyl-cholinesterase | Acetyl group | Choline | Acetyl-CoA |
| D. | Acetylcholine | Cholinergic receptor | Acetyl-CoA | Choline | Acetyl group | Acetyl-cholinesterase |
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The following graph shows an action potential in a mouse neurone after stimulation with a pulse of current.
What is the threshold potential needed to open voltage gated sodium channels in this neurone?
-70mV
-50mV
-30mV
+50mV
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The opening of axon membrane voltage gated potassium channels are responsible for which part of the action potential?
Repolarisation of the membrane.
Depolarisation of the membrane.
Hyperpolarisation of the membrane.
Signalling vesicular release of neurotransmitters.
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It is thought that conditions such as schizophrenia are caused by an overabundance of the neurotransmitters serotonin and dopamine in some regions of the brain.
Given this is the case, which drug mode of action could work in treating symptoms of schizophrenia?
Increased permeability of the presynaptic neurone to calcium.
Increased reuptake of serotonin and dopamine by pre synaptic neurones.
Release of acetylcholinesterase into the presynaptic cleft.
Blockage of serotonin and dopamine receptors in postsynaptic neurones.
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Which of the following statements about myelinated nerve fibres are correct?
II only
I and II only
II and III only
I, II, and III
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The diagram below shows the change in membrane potential during an action potential.
Which of the following best describes the events indicated by the label X?
| Sodium channels | Potassium channels | Membrane potential | |
| A | open | closed | decreasing |
| B | closed | open | increasing |
| C | closed | open | decreasing |
| D | open | closed | increasing |
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The diagram below shows a sensory neurone connected to its associated receptor cells.
Which best describes the function of the structure labelled A?
Contains most cellular structures
Acts as an electrical insulator
Transmit impulses to the spinal cord
Transmit and recieve impulses to other neurones
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The diagram below shows a sodium-potassium pump within the axon membrane of a neurone.
What is the role of active transport in the transmission of nerve impulses by neurones?
Establishes the resting potential needed for impulse transmission by pumping sodium ions out of the axon and potassium ions into the axon.
Depolarisation of the axon by moving sodium ions across the membrane into neurone.
Establishes the resting potential needed for impulse transmission by moving sodium ions into the axon and potassium ions out of the axon.
Initiates the action potential needed for the transmission of an impulse by pumping calcium ions into the axon.
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Which line of the table represents a neurone at its resting potential?
| Concentration of ions inside neurone | Cell surface membrane permeability to Na⁺ | Level of activity of Na⁺/K⁺ pump | ||
| Sodium (Na⁺) | Potassium (K⁺) | |||
| A | high | low | high | active |
| B | high | low | low | inactive |
| C | low | high | high | inactive |
| D | low | high | low | active |
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Membrane channel proteins are essential for the normal functioning of nerves.
Which process in nerves does not require a membrane protein?
Active transport of sodium.
Depolarisation during an action potential.
Binding of neurotransmitters.
Diffusion of neurotransmitters.
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The use of pesticides is a cause of controversy due to its impact on pollinators such as bees.
What effect do these pesticides have on the nervous system of insects?
They prevent acetylcholinesterase from breaking down acetylcholine.
They inhibit depolarisation in the presynaptic neurone which increases the level of acetylcholine.
They block synaptic transmission by binding with postsynaptic acetylcholine receptors.
They produce an inhibitor that promotes the binding of acetylcholine.
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