Describe the factors that affect enzyme activity. Explain the effect
on enzyme activity, and explain what is happening to the enzyme or to
the reaction

Enzymes are gobular proteins that function to catalyze specific
reactions in the body. The enzyme rate is affected by Temperature, pH
levels, Hydrogen ion concentration and possibly temperature.
Most enzymes are substrate-specific in a fixed area i.e either acidic
or basic, so they may denature if any of  the factors mentioned above
come in play.
Sometimes enzymes are inhibited by coenzymes, or substrate-like molecules. 

But, most of this will be in Your general bio text ;)

Note about temperature:
Temperatures lower than that of the natural environment the enzyme
resides in may slow the reaction or destroy the enzyme.
Temperatures higher may increase the reaction rate or destroy the enzyme.  

The reasons for slower and faster reaction rates are because the
temperature is directly proportional to the kinetic energy of the
enzyme and surrounding molecules.  Higher kinetic energy makes for a
higher chance for the enzyme to bump into molecules that it will react
with.  Kinetic energy and temperature relationships can easily be
found in a general physics or chemistry text.

lol