Answer:
One possible cause of persistent sadness could be depression
Explanation:
Function of an enzyme is to lower reaction's activation energy and to increase speed of a reaction, but to make it happen, enzyme and substrate must fit spatially. The shape of an enzyme is essential to make enzyme-substrate complex - if active site of an enzyme doesn't fit to substrate, there won't be a enzyme-catalised reaction.
Answer:
depolarization leading to action potentials
Explanation:
The voltage-gated Na+ channels are responsible for rapid depolarization phase of the action potential. Action potential generation require depolarization of neuronal membrane which is acquired by influx of sodium ions through voltage gated sodium ion channels. If the Na+ channels are blocked, there will be no influx of sodium ions to cause depolarization hence action potential will not be generated.