Synapses and Action Potentials

Which of the following statements about synaptic plasticity is correct?

• Synaptic plasticity only involves the strengthening of neural synapses.

• Synaptic plasticity only occurs during infancy.

• Synaptic plasticity involves structures of neurons physically changing in response to activity or experience.

Answer explanation

The correct statement is that synaptic plasticity involves structures of neurons physically changing in response to activity or experience, reflecting the dynamic nature of neural connections.

How does neurotransmitter cross the synaptic cleft?

• Facilitated diffusion

• simple diffusion

• carrier mediated transport

• osmosis

Answer explanation

Neurotransmitters cross the synaptic cleft primarily through simple diffusion. They move from an area of higher concentration in the presynaptic neuron to an area of lower concentration in the postsynaptic neuron.

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'.

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.

Small-molecule neurotransmitters are _______ for _______.

• taken back into the presynaptic terminal; degradation

• taken back into the presynaptic terminal; reuse

• taken up by the postsynaptic cell; degradation

• taken up by the postsynaptic cell; reuse

• scattered in the synaptic cleft; reuse

Answer explanation

Small-molecule neurotransmitters are taken back into the presynaptic terminal for reuse after they have transmitted signals. This process allows the neuron to recycle neurotransmitters efficiently.

Which of the following statements about action potentials is correct?

• Action potentials are graded responses that vary in magnitude.

• Action potentials are all-or-nothing events that occur when a threshold is reached.

• Action potentials can travel in both directions along an axon.

• Action potentials decrease in strength as they travel along an axon.

What is the primary role of the sodium-potassium pump in neurons?

• To generate action potentials by allowing sodium ions to enter the cell.

• To maintain the resting membrane potential by pumping sodium out and potassium into the cell.

• To release neurotransmitters into the synaptic cleft.

• To facilitate the binding of neurotransmitters to receptors.