Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Problem:Passage: Enzymes are extremely efficient in speeding up reactions. They can catalyze up to several million reactions per second. As a result, the difference in rates of biochemical reactions with and without enzymes may be enormous. A typical biochemical reaction might take hours or even days to occur under normal cellular conditions without an enzyme, but less than a second with an enzyme. Answer: speed it up
Solution:
Enzymes in cellular reactions work to do what to the reaction?