Final answer:
A ligand-receptor interaction involves a ligand binding to a receptor on the cell surface, activating a signaling pathway. An enzyme-substrate reaction occurs when a substrate binds to the active site of an enzyme, catalyzing a specific chemical reaction.
Step-by-step explanation:
In a ligand-receptor interaction, a ligand binds to a receptor on the cell surface, activating a signaling pathway and causing a change in the cell's environment. This interaction is part of cell communication and plays a role in processes such as hormone signaling. In contrast, an enzyme-substrate reaction occurs when a substrate binds to the active site of an enzyme. The enzyme catalyzes a specific chemical reaction, converting the substrate into a product. Enzymes are involved in various metabolic pathways in cells. The key difference between these two interactions is their function: ligand-receptor interactions mediate cell signaling, while enzyme-substrate reactions are involved in catalyzing specific chemical reactions.