What happens when electrons inside an atom get excited“?
A. They stay in their current energy
level
B. They jump down an energy level
and absorb energy in the process
C. They jump up an energy level and
release energy in the process

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.