Which enzyme when made to act on a DNA molecule creates blunt ends/flush ends?

Options

A. Sma I
B. Hind II
C. EcoR I
D. Bam HI

Answer

To answer the question "Which enzyme when made to act on a DNA molecule creates blunt ends/flush ends?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for an enzyme that, when it acts on DNA, produces blunt or flush ends. Blunt ends are characterized by a straight cut across the DNA, resulting in no overhanging bases.

2. **Identifying the Options**: The question provides several enzyme options, and we need to evaluate each one to determine which produces blunt ends.

3. **Evaluating Option 1 - EcoRV**:
- EcoRV is a restriction enzyme known for cutting DNA in a way that results in blunt ends.
- This enzyme cuts straight through the DNA, creating ends that are flush with each other.

4. **Evaluating Option 2 - HindIII**:
- HindIII is another restriction enzyme, but it produces sticky ends rather than blunt ends.
- Sticky ends have overhanging bases, which are useful for certain types of DNA ligation but do not fit the criteria of blunt ends.

5. **Evaluating Option 3 - EcoRI**:
- EcoRI is also a restriction enzyme that produces sticky ends.
- Like HindIII, it does not create blunt ends.

6. **Evaluating Option 4 - BamHI**:
- BamHI is another restriction enzyme that produces sticky ends.
- Therefore, it does not meet the requirement of producing blunt ends.

7. **Conclusion**: After evaluating all the options, the only enzyme that creates blunt ends when acting on a DNA molecule is **EcoRV**.

### Final Answer:
The enzyme that creates blunt ends when acting on a DNA molecule is **EcoRV**.

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