What effect does a catalyst have on activation energy?
A catalyst will decrease activation energy.
So why is this important? Enzymes will make reactions occur much more easily, quickly and more efficiently than they ever would without the enzyme.
Here is a video of an enzyme demonstration I like to share with my students. The video shows how an enzyme present in our saliva (spit) can aid in the process of digestion by acting on starches present in the foods we eat.
Video from: Noel Pauller
Hope this was helpful!