descride the "lock and key" throy of enzymes?

Answer 1

This the theory that the substrate of an enzyme, say lactose sugar, has a shape like a key that exactly fits the enzyme lactase (alpha-galactosidase). So when the sugar inserts itself into the active site of the enyme, everything fits, the sugar is bound in place, and the water and hydrogen ions come together to hydrolyze it to glucose and galactose.

The alternate theory has the sugar forcing the enzyme to accomodate it.

Answer 2

basically,it means that only the right enzyme can fit into the right site, that is all it means, and they call it lock and key because a wrong key wont fit the wrong lock.