Imagine that you and your friend (of equal size and weight) are competing in a competition to see who can run up ten flights of stairs faster. It takes you 100 seconds to run up the ten flights of stairs, but it takes your friend
120 seconds. Who did the most work? Who exerted the most power?

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit. there is a precise compatibility between the active site and the lactose molecule. specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed. reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.