Question

what is the “lock and key” theory of enzyme action?

Explanation:

The "lock and key" theory of enzyme action is a model proposed by Emil Fischer in 1894. According to this theory, the enzyme (lock) has a specific three - dimensional shape (active site) that is complementary to the shape of its substrate (key). Just as a key fits into a specific lock, the substrate fits precisely into the active site of the enzyme. Once the substrate binds to the enzyme (forming an enzyme - substrate complex), the enzyme catalyzes the chemical reaction, and then the product is released. This theory emphasizes the specificity of enzyme - substrate interactions.

Answer:

The "lock and key" theory states that the enzyme (lock) has a specific active site shape complementary to its substrate (key). The substrate fits into the enzyme's active site, forming an enzyme - substrate complex. The enzyme then catalyzes the reaction, and the product is released. It emphasizes enzyme - substrate specificity.