Question

Which curve shows the course of the reaction in the presence of an enzyme--the black curve or the red curve? Which line represents the activation energy for that reaction--a, b, or c?

Answer 1

I found the attached image on the internet and it really helps complete this exercise.

First question:
In the presence of an enzyme, the course of the reaction is shown by the red curve. The necessary energy to make a reaction occur is less when there is an enzyme to help the reaction happen. Enzymes work as catalysts that act over substrates converting them into different molecules in a much accelerated way then it would happen without the enzyme's help, if it would happen at all.

Second question:
The activation energy is represented by line B. The activation energy is the energy needed to be available for a reaction to happen. If we compare it with line A, which represents the activation energy necessary for a reaction without an enzyme, we can see how much less energy is necessary to dispend when an enzyme is part of the reaction. Line C represents the energy resultant from the reaction.