Enzymes play a crucial role in the body by acting as biological catalysts that speed up chemical reactions. Without enzymes, many of the reactions necessary for life would occur too slowly to sustain metabolic processes. They lower the activation energy required for reactions to proceed, allowing processes such as digestion and energy production to occur efficiently. Each enzyme is specific to a particular reaction or substrate, and factors like temperature and pH can affect their activity. Overall, enzymes are essential for breaking down food, synthesizing molecules, and regulating biochemical pathways.