The plant cell wall
a. is found just inside the plasma membrane. b. is a protective structure made of cellulose fibrils. c. regulates the composition of the cytoplasm. d. makes food by converting light energy to chemical energy. e. is very similar to the animal cell wall.

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.