The ''lock and key'' model of enzyme action illustrates that a particular enzyme molecule

Options

A. May be destroyed and resynthesised several times
B. Interacts with a specific type of substrate molecule
C. Reacts at identical rates under all conditions
D. Forms a permanent enzyme-substrate complex

Answer

### Step-by-Step Solution:

1. **Understanding the Lock and Key Model**:
- The lock and key model describes how enzymes interact with substrates. In this model, the enzyme's active site (the "lock") has a specific shape that perfectly fits a particular substrate (the "key"). This specificity is crucial for the enzyme's function.

2. **Analyzing the Options**:
- **Option A**: "May be destroyed and re-synthesized several times."
- This is incorrect because enzymes are not destroyed in the process of catalyzing a reaction; they can be reused multiple times.

- **Option B**: "Interacts with a specific type of substrate molecule."
- This is correct. The lock and key model emphasizes the specificity of enzymes for their substrates.

- **Option C**: "Reacts at identical rates under all conditions."
- This is incorrect. Enzyme activity can vary based on conditions such as temperature and pH.

- **Option D**: "Forms a permanent enzyme-substrate complex."
- This is also incorrect. The enzyme-substrate complex is temporary; the enzyme is released after the reaction.

3. **Conclusion**:
- The correct answer is **Option B**: "interacts with a specific type of substrate molecule."