Question 1
The diagram below refers to a synapse.
Which statement describes events occurring at a synapse?
acetylcholine is broken down by enzymes so that it can bind to structure K
an action potential causes structure J to close
structure J is a voltage gated Ca2+ channel
structure L is released by exocytosis
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Question 2
The diagram below refers to a synapse.
GABA is a neurotransmitter. GABA reduces the number of action potentials in the postsynaptic neurone by opening chloride ion channels in the postsynaptic membrane.
Which statement describes the action of GABA?
GABA binds to structure K in competition with acetylcholine
GABA causes hyperpolarisation of the postsynaptic membrane
GABA causes depolarisation of the postsynaptic membrane
GABA inhibits release of neurotransmitter from structure L
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Question 3
Neurotransmitters such as GABA are found at synapses within the human brain and are known as inhibitory neurotransmitters.
GABA binds to receptors in the postsynaptic membrane and causes potassium ion channels to open.
Why does this prevent an action potential in the postsynaptic neurone?
because potassium ions diffuse out of the postsynaptic neurone causing depolarisation
because potassium ions diffuse out of the postsynaptic neurone causing hyperpolarisation
because potassium ions diffuse into the postsynaptic neurone causing depolarisation
because potassium ions diffuse into the postsynaptic neurone causing hyperpolarisation
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Question 4
What happens when neurotransmitter molecules bind to receptor sites on the postsynaptic neuron?
neurotransmitter molecules are immediately broken down
an inhibitory postsynaptic potential is always generated
a new action potential may be initiated in the postsynaptic neuron
the presynaptic neuron is stimulated
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Question 5
What is the primary purpose of synaptic vesicles?
to store calcium ions needed for neurotransmission
to absorb excess neurotransmitter from the synaptic cleft
to provide energy for the synaptic transmission
to contain and release neurotransmitters into the synaptic cleft
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Question 6
During synaptic transmission, the opening of which ion channels directly triggers the release of neurotransmitter?
potassium
calcium
sodium
chloride
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Question 7
What effect does the enzyme acetylcholinesterase have in the synapse?
it generates action potentials in the presynaptic neuron
it facilitates the release of more acetylcholine
it stimulates the growth of synaptic vesicles
it breaks down acetylcholine in the synaptic cleft
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Question 8
What is the consequence of the influx of sodium ions into the postsynaptic neuron?
it leads to the neuron becoming negatively charged
it decreases the likelihood of an action potential
it inhibits neurotransmitter release from the presynaptic neuron
it can generate a new action potential
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Question 9
What determines the specific response of the postsynaptic neuron to a neurotransmitter?
the type of receptor that the neurotransmitter binds to
the frequency of neurotransmitter release
the number of neurotransmitter molecules released
the type of ion channel that is opened
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Question 10
Which neurotransmitter is responsible for muscle movement?
dopamine
acetylcholine
GABA
serotonin
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