6.5C&D

6.5C&D

By Jessica HS)

6.5C: Synapses

6.5D: Acetylcholine​

Action potential is the electric signal that is sent down the axon of a neuron. ​Neurons need to be able to transmit action potentials to other neurons.

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​Reminders from 6.5B:

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Multiple Choice

If schizophrenia is caused by an overabundance of the neurotransmitters dopamine and serotonin in the synapses of some areas of the brain, which drug action could work in treating the symptoms?

• Release of cholinesterase into the synaptic cleft

• Increased re-uptake of dopamine and serotonin by presynaptic neurons

• Increased permeability of the presynaptic neuron to sodium

• Blockage of dopamine and serotonin receptors on presynaptic neurons

Multiple Choice

The diagram below shows part of the membrane of a neuron. What stage of the action potential does it depict?

• Depolarization

• Repolarization

• Resting potential

• Hyperpolarization

Multiple Choice

How do neonicotinoid pesticides cause paralysis and death in insects?

I. Acetylcholine receptors are blocked.

II. Cholinesterase fails to break down the pesticide.

III. The pesticides bind to presynaptic receptors.

• I only

• I and II only

• I and III only

• I, II and III

Multiple Choice

Common pesticides used by gardeners contain neonicotinoids.

What is the effect of a neonicotinoid pesticide on the transmission of a nerve impulse between neurons in an insect?

• It prevents the release of acetylcholine from the presynaptic membrane.

• It widens the synaptic cleft so diffusion of acetylcholine across the gap is slower.

• It irreversibly binds with acetylcholine receptors on the postsynaptic membrane.

• It interferes with the enzymatic breakdown of acetylcholine by acetylcholinesterase.

Multiple Choice

What process is blocked by neonicotinoid pesticides in insects?

• Transmission of the nerve impulse in the presynaptic neuron

• Formation of the synaptic vesicles

• Release of the neurotransmitter

• Binding of neurotransmitters to postsynaptic acetylcholine receptors