With the increase is substrate concentration the rate of enzymatic activity increases

Options

A. Until half the number of active sites on enzyme molecule are filled by substrate
B. Until all the active sites on the enzyme are filled by substrate
C. Until all substrate molecules are used up
D. None of the above

Answer

To solve the question regarding the relationship between substrate concentration and the rate of enzymatic activity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Enzymatic Activity**: Enzymes are biological catalysts that speed up chemical reactions. The rate of enzymatic activity is influenced by several factors, including substrate concentration.

2. **Effect of Substrate Concentration**: As substrate concentration increases, the rate of enzymatic activity also increases. This is because more substrate molecules are available to bind to the active sites of the enzyme.

3. **Saturation Point**: However, this increase in rate continues only up to a certain point. Once all the active sites on the enzyme are occupied by substrate molecules, the enzyme becomes saturated. At this saturation point, adding more substrate will not increase the rate of reaction because there are no free active sites available for additional substrate to bind.

4. **Analyzing the Options**:
- **Option A**: "Until half the number of active sites on enzyme molecule are filled by the substrate" - This is incorrect because the rate can still increase until saturation is reached.
- **Option B**: "Until all the active sites on enzymes are filled by the substrate" - This is correct because the rate of reaction increases until all active sites are occupied.
- **Option C**: "Until all substrate molecules are used up" - This is incorrect as it does not consider the saturation of enzyme active sites.
- **Option D**: "None of the above" - This is also incorrect since option B is correct.

5. **Conclusion**: The correct answer is **Option B**: "Until all the active sites on enzymes are filled by the substrate."