Which of the following cannot be digested by the enzymes in an animals digestive tract?

Cellulose

Enzymes and substrates are often specific for one another. They have shapes that can be modified to fit into each other which allows them to bind together (induced fit). T ogether, Enzymes and substrates undergo some transformations as they interact. They interact by forming hydrogen bonds, covalent bonds and what is also called hydrophobic interactions.

The enzyme returns to its original shape and state after the reaction but the substrate is often modified or changed completely into a new, different product.