Neurotransmitter

4 - Calcium ions trigger the fusion of vesicles containing.. with the.. membrane

5 - .. diffuses across the synaptic.. and binds to receptors in the.. membrane

Answer explanation

Calcium ions trigger the fusion of vesicles containing acetylcholine with the presynaptic membrane. Acetylcholine then diffuses across the synaptic cleft and binds to receptors in the postsynaptic membrane.

Tags

NGSS.HS-LS2-3

6 - Acetylcholine binding opens chemical-gated.. .. channels, so .. .. enter and.. the postsynaptic membrane

Answer explanation

Acetylcholine binding opens chemical-gated sodium channels, allowing sodium ions to enter the postsynaptic membrane, leading to depolarization.

Which of the following best describes the role of synaptic vesicles in neurotransmission?

• They store neurotransmitters and release them into the synaptic cleft upon stimulation.

• They transport ions across the synaptic cleft.

• They generate action potentials in the presynaptic neuron.

• They degrade neurotransmitters after signal transmission.

Answer explanation

Synaptic vesicles are crucial in neurotransmission as they store neurotransmitters and release them into the synaptic cleft when the neuron is stimulated, facilitating communication between neurons.

Which event is the first in the series of events that take place during chemical synaptic transmission?

• Neurotransmitter binds to its receptors.

• Influx of Ca²⁺ in the presynaptic terminal.

• Voltage-gated Ca²⁺ channels open.

• Neurotransmitter is released into the synaptic cleft.

• Synaptic vesicles fuse with the presynaptic membrane.

Answer explanation

The first event in chemical synaptic transmission is the opening of voltage-gated Ca2+ channels. This allows Ca2+ to enter the presynaptic terminal, triggering subsequent events like neurotransmitter release.

The figure shows an electron micrograph of a chemical synapse in the cerebral cortex. Which statement about this synapse is accurate?

• Inside the postsynaptic neuron are synaptic vesicles, which fuse with the membrane in the postsynaptic density.

• Inside the presynaptic neuron are synaptic vesicles, which fuse with the membrane in the active zone.

• Inside the presynaptic neuron are synaptic vesicles, which fuse with the membrane in the postsynaptic density.

• A gap junction connects the two neurons via connexons that span the pre- and postsynaptic membranes.

Answer explanation

The correct statement is that inside the presynaptic neuron are synaptic vesicles, which fuse with the membrane in the active zone. This is where neurotransmitter release occurs, facilitating communication between neurons.

Tags

NGSS.HS-LS2-3

The conversion of signal at presynaptic membrane is

• Electrical signal to chemical signal

• Chemical signal to electrical signal

• Potential signal to electrical signal

• Potential signal to chemical signal

Answer explanation

The presynaptic membrane converts an electrical signal (action potential) into a chemical signal (neurotransmitter release) to communicate with the postsynaptic neuron, making 'Electrical signal to chemical signal' the correct choice.

The conversion of signal at postsynaptic membrane is

• Electrical signal to chemical signal

• Chemical signal to electrical signal

• Potential signal to electrical signal

• Potential signal to chemical signal

Answer explanation

At the postsynaptic membrane, neurotransmitters (chemical signals) bind to receptors, leading to changes in membrane potential, thus converting chemical signals into electrical signals. Hence, the correct answer is 'Chemical signal to electrical signal'.

What is most likely to happen if a post-synaptic neuron is depolarized? Hyperolarized?

• Depolarized- becomes more positive, action pot more likely

  Hyperpolarized- becomes very negative, action pot less likely

• Depolarized- becomes more negative, action pot less likely

  Hyperpolarized- becomes very positive, action pot more likely

Answer explanation

When a post-synaptic neuron is depolarized, it becomes more positive, increasing the likelihood of an action potential. Conversely, if it is hyperpolarized, it becomes very negative, making an action potential less likely.

What is the specific neurotransmitter that stimulates the muscle contraction?

• GABA

• Acetylcholine

• Serotonin

• Dopamine

What is the name of the structure that stores neurotransmitters?

• Synaptic cleft

• Acetylcholine

• Receptors

• Synaptic vesicles