Answer:
Enzymes' shapes are important because it determines the specific substrate it will act onto.
Step-by-step explanation:
The shape of the enzymes are explained by two theories, which are Lock and Key Theory and Induced Fit Theory.
Lock and Key Theory
This was first coined by Emil Fischer in 1894. Just like how a key has a specific keyhole, enzymes' active sites are supposed to act on specific substrates to produce a catalyzed effect. Incorrectly shaped keys or enzymes will not fit into a lock (substrate) not assigned for it.
Induced Fit Theory
this theory was proposed for the substrates that do not qualify for the Lock-and-Key theory, or enzymes that have more than one active sites. It is said that the substrate determines the final shape of the enzyme, and that the enzyme is somehow pliable. The enzyme is then modified by the substrate to form an enzyme-substrate complex. This explains why two or more enzymes can catalyze a single substrate.
Additional notes:
For enzymes to work, they may need specific molecules.
A coenzyme may be metal ions (iron, copper, magnesium) or organic molecules (Vitamins B2, B3, B8) which attach to an enzyme to form a holoenzyme. An apoenzyme is an enzyme with only its protein part sans the cofactor.