Question

How do enzymes function in biological systems?

Answer 1

Enzymes are proteins which act as biological catalysts.

Explanation:

Please see my previous answer to a very similar question.
http://socratic.org/questions/what-are-enzymes?source=search

Here is a video which demonstrates how salivary amylase (a digestive enzyme found in our spit) starts the process of digestion by breaking down starch molecules present in the foods we eat.

video from: Noel Pauller

Hope this was helpful!