Catalyst

A catalyst is a substance that accelerates the rate of a chemical reaction without itself being consumed or permanently altered in the process. Catalysts work by providing an alternative pathway with a lower activation energy, allowing reactant molecules to undergo the reaction more readily. 

After the reaction, catalysts are typically recovered unchanged and can be reused in subsequent reactions. Catalysts play a critical role in various industrial processes, such as chemical synthesis and environmental remediation, as well as in biological systems, where they facilitate essential metabolic processes.

Enzyme

Enzyme is a biological catalyst that alters the speed of a reaction, accelerating reactions within a living organism. It does this by reducing the activation energy required for the chemical reaction. Activation energy is referred to as the amount of energy required to kickstart a chemical reaction. 

Enzymes are highly specific, catalyzing particular reactions or groups of reactions by binding to specific molecules, called substrates, at their active sites. Through this binding, enzymes facilitate the conversion of substrates into products, typically by lowering the activation energy required for the reaction to occur. Enzymes are necessary for numerous cellular processes, including metabolism, digestion, DNA replication, and cellular signaling. They are produced by living cells and are essential for maintaining life.

Example: Digestive enzymes, such as amylase, lipase, and protease, are crucial for breaking down ingested food into nutrients that can be absorbed and utilized by the body. Without these enzymes, the process of digestion would be exceedingly slow. For instance, if we didn’t produce digestive enzymes, it would take an estimated 2 to 3 weeks to fully digest a meal. However, with the aid of enzymes, digestion typically occurs within a few hours, allowing nutrients to be absorbed efficiently and providing the energy necessary for sustaining life.