Biology Question

[joe001]

Hello,

I would appreciate anyone's help on this question.

The answer is F. But I’m wondering why it’s correct to say the “signal is transmitted across the synapse by diffusion”. Aren’t neurotransmitters released by exocytosis, which is active transport, and not diffusion?

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[deleted1102547]

Hello,

I would appreciate anyone's help on this question.

View attachment 343844

The answer is F. But I’m wondering why it’s correct to say the “signal is transmitted across the synapse by diffusion”. Aren’t neurotransmitters released by exocytosis, which is active transport, and not diffusion?

Neurotransmitters are released by exocytosis, but they are not actively transported across the synapse. The active transport ends once the vesicle opens and releases the neurotransmitters. From there, they just randomly diffuse across the synapse until they reach the target receptors on the other side. That is not an active process, so you couldn't say that the "signal is transmitted across the synapse by active transport”.

 

[joe001]

I see. Thank you.