Practice!

Sample Problem

Enzymes are [check all that apply]

(A) proteins

(B) cofactors

(C) catalysts

(D) substrates

Solution

(A) and (C) are correct. Enzymes are special proteins that act as catalysts in chemical reactions. Cofactors (B) are minerals that help enzymes work even faster, and substrates (D) are the molecules that enzymes work on.