5. During resting membrane potential, a sodium ion the cell will have electrical potential energy and a sodium ion the cell will have electric potential energy. A. Inside low outside high

B. Inside high outside low

C. Inside high outside high

D. Inside low outside low

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.