The inhibitor which closely resembles the substrate in its molecular structure and inhibits the enzyme activity by biniding to the active site of the enzyme is called

Options

A. feedback inhibitor
B. non-competitive inhibitor
C. competitive inhibitor
D. allosteric modulator.

Explanation

To answer the question regarding the type of inhibitor that closely resembles the substrate in its molecular structure and inhibits enzyme activity by binding to the active site, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Enzyme Inhibition**:
- Enzymes are biological catalysts that speed up chemical reactions in the body. They have specific sites called active sites where substrates bind to undergo a reaction.

2. **Types of Inhibitors**:
- There are different types of enzyme inhibitors, which can be classified based on how they interact with the enzyme and the substrate.

3. **Identifying the Inhibitor Type**:
- The question specifies that the inhibitor resembles the substrate in molecular structure. This is a key detail.
- Inhibitors that resemble the substrate and compete for the active site of the enzyme are known as **competitive inhibitors**.

4. **Mechanism of Competitive Inhibition**:
- Competitive inhibitors bind to the active site of the enzyme, preventing the actual substrate from binding. This reduces the rate of reaction because the substrate cannot access the active site.

5. **Examples of Competitive Inhibitors**:
- An example of a competitive inhibitor is penicillin, which inhibits bacterial enzymes necessary for cell wall synthesis by binding to their active sites.

6. **Conclusion**:
- Based on the information provided, the correct answer to the question is that the inhibitor which closely resembles the substrate and binds to the active site is called a **competitive inhibitor**.

### Final Answer:
The inhibitor which closely resembles the substrate in its molecular structure and inhibits the enzyme activity by binding to the active site of the enzyme is called a **competitive inhibitor**.

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