Final answer:
Adding regulatory molecules can either increase or decrease enzyme activity. Activators bind to allosteric sites and promote substrate binding, while inhibitors bind to allosteric sites and prevent substrate binding.
Step-by-step explanation:
When regulatory molecules are added to an enzyme, they can either increase or decrease the enzyme's activity, depending on the type of regulatory molecule and its effect on the enzyme.
In the case of an activator, the regulatory molecule binds to an allosteric site on the enzyme, causing a conformational change in the enzyme's active site. This change makes it easier for the enzyme to bind to its substrate, leading to an increase in enzyme activity. On the other hand, an inhibitor molecule can also bind to an allosteric site on the enzyme. This binding causes a conformational change that makes it more difficult for the enzyme to bind to its substrate, resulting in a decrease in enzyme activity.