The hero has something that sets her apart from others at the beginning. * A. The Temptation B. Crossing the Threshold C. An Unusual Birth/Early Childhood D. The Return Home

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.