20. Enzymatic reactions can be expressed in which of the following chemical notations?
a. S + P = E
b. P + P = E
c. E + S = P
d. S + S = P

21. Enzymes that remove functional groups from a substrate without adding water, or that add functional groups to a double bond, are called
a. oxidoreductases.
b. transferases.
c. hydrolases.
d. lyases.

ssss22. Chemically, most enzymes are
a. proteins.
b. lipids.
c. nucleic acids.
d. carbohydrates.