Question

Key lock theory given by Fisher (1898) explain the mode of action of

• A. Hormone
• B. Enzyme
• C. ATP
• D. Herbicides

Hint:

Enzyme mechanisms:
Lock and Key Model $\rightarrow$ Emil Fischer (1898, Rigid active site).
Induced Fit Model $\rightarrow$ Daniel Koshland (1958, Flexible active site).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Enzymatic catalysis depends on stereospecific structural complementarity between the enzyme's active site and its substrate molecule.
Key Formula or Approach:
\[ \text{Enzyme (E)} + \text{Substrate (S)} \rightleftharpoons [\text{ES Complex}] \longrightarrow \text{Enzyme (E)} + \text{Product (P)} \]

Step 2: Detailed Explanation:
In 1898, German chemist Emil Fischer proposed the 'Lock and Key Model' of enzyme action.
Fischer postulated that the enzyme's active site has a rigid, pre-formed geometric shape (the lock) into which only a specific substrate molecule with a complementary 3D shape (the key) can fit precisely to form the enzyme-substrate intermediate complex.

Step 3: Final Answer:
Hence, the key lock theory explains the mode of action of Enzymes, corresponding to option (B).