The second statement is correct. Once the enzyme binds to the specific substrate molecule, structural changes can occur in the enzyme's active site to accommodate the product which is the substrate in a transitional state until the reaction is complete to yield the final product.
When the substrate interacts with the enzyme, it undergoes a chemical reaction that allows the atoms to move relative to each other, and the bonds possibly lengthen or shorten which causes the most reactive groups to move closer to each other causing a shape change.
This shape change in the enzyme makes the substrate more amenable to alteration, as it holds the substrate in a transitional state, which helps speed up the reaction that the enzyme catalyzes.
