Final answer:
Cells differ in their enzymes because each cell type has unique functions and demands, necessitating the regulation of enzyme production and activity to meet specific metabolic needs and respond to environmental conditions.
Step-by-step explanation:
The enzymes of various tissues differ to meet the specific metabolic needs and functional demands of each cell type. In the body, different cells such as those of the stomach, skin, blood, and nerve have unique roles, leading to distinct energetic demands and environmental conditions. For instance, digestive cells become highly active after a meal to break down nutrients, demanding a different set of enzymes than those required by fat storage cells or skin cells. The control of metabolism is achieved through the regulation of these enzymes, which is governed by various factors including gene expression, environmental changes, and cellular development. The specificity of enzymes is determined by the structure of their active sites, enabling precise biochemical reactions necessary for cellular function.