Final answer:
Without an enzyme, few substrate molecules are able to reach the transition state due to insufficient kinetic energy or improper orientation for successful collisions. Enzymes lower the free energy of activation and facilitate the reaction to occur more efficiently.
Step-by-step explanation:
Without an enzyme, only a few substrate molecules reach the transition state. Enzymes play a crucial role in lowering the free energy of activation, which is the energy necessary for a reaction to occur. This energy threshold must be exceeded for the substrates to convert into products.
In the absence of an enzyme, substrates may lack sufficient kinetic energy or could be incorrectly oriented to successfully collide and react. Enzymes facilitate the proper orientation and energy required for the reaction, allowing more substrate molecules to achieve the transition state, an unstable high-energy state that leads to the formation of products. Without enzymes to stabilize this state and lower the activation energy, most molecular collisions would not result in a reaction, thus significantly reducing the efficiency of the chemical process.