Which ion triggers the fusion of synaptic vesicles with the plasma membrane for exocytosis?

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BlackTom AI · Accepted Answer

The question asks which ion triggers the fusion of synaptic vesicles with the plasma membrane during exocytosis.
Option 1: K+. Potassium ions mainly influence membrane potential and repolarization, but they do not directly trigger the vesicle fusion machinery for neurotransmitter release. Therefore, this choice is incorrect.
Option 2: Cl-. Chloride ions are primarily involved in setting inhibitory postsynaptic potentials and maintaining ionic balance; they are not the trigger for vesicle fusion in exocytosis. This makes this option incorrect.
Option 3: Ca2+. Calcium ions are the key trigger for vesicle fusion at the presynaptic terminal. Influx of Ca2+ through voltage-gated calcium channels upon an action potential binds to sensors like synaptotagmin, promoting SNARE complex-mediated fusion and neurotransmitter release. This is the correct mechanism.
Option 4: Na+. Sodium ions drive the depolarization phase of the action potential and are essential for signaling, but they do not directly trigger the vesicle fusion event in exocytosis. Thus, this option is incorrect.
In summary, exocytosis at the synapse is calcium-dependent, whereas the other ions play different roles in electrical signaling and membrane dynamics without directly initiating vesicle fusion.

BIOL-2401-099 A&P I Exam 3 Electrically Excitable Tissues- Requires Respondus LockDown Browser

Which ion triggers the fusion of synaptic vesicles with the plasma membrane for exocytosis?

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BIOL-2401-099 A&P I Exam 3 Electrically Excitable Tissues- Requires Respondus LockDown Browser

Which ion triggers the fusion of synaptic vesicles with the plasma membrane for exocytosis?

查看解析

登录即可查看完整答案

类似问题

Which of the following explains why one-way synaptic transmission occurs?

Question at position 3 Select all the ways a neurotransmitter can exit the space between neurons.DiffusionReuptake/recyclingAxon travelEnzymes will digest the neurotransmitter.Immune cells will attack.

At a synapse between two neurons, the dendrites release the neurotransmitters.

Consider a neuron-neuron synapse. Match the description with the presynaptic or postsynaptic neuron. 1: Action potential travels away from the synapse via this neuron. ____ 2: First in the chain of neurons. ____ 3: Second in the chain of neurons. ____ 4: Releases neurotransmitter. ____

The theory of quantal mechanism of neurotransmission was based on electrophysiology providing evidence for quantal activity in synaptic transmission combined with electron microscopy revealing vesicles near terminal boutons.

Which of the following is the correct sequence of events that occur during synaptic transmission?

What accounts for the longest delay in neuronal signalling?

更多留学生实用工具

希望你的学习变得更简单

Consider a neuron-neuron synapse. Match the description with the presynaptic or postsynaptic neuron. 1: Action potential travels away from the synapse via this neuron. 2: First in the chain of neurons. 3: Second in the chain of neurons. 4: Releases neurotransmitter.