The "Lock and Key Model" is a scientific concept used to explain how enzymes and substrates interact. In this model, the enzyme is likened to a lock, while the substrate is compared to a key. Just as a specific key fits into a particular lock, a substrate must have a specific shape to fit into the active site of an enzyme, allowing a biochemical reaction to occur. This model emphasizes the specificity of enzyme action, meaning that each enzyme only catalyzes a particular reaction with its corresponding substrate. The enzyme-substrate complex formed during this interaction is crucial for various biological processes, including metabolism and DNA replication.