Identify the restriction endonuclease that will provide sticky ends of DNA strands :

Options

A. Hind II
B. Sma I
C. Eco RI
D. Hae III

Answer

To identify the restriction endonuclease that provides sticky ends of DNA strands, we can analyze the options provided in the question step by step.

### Step 1: Understand the Concept of Restriction Endonucleases
Restriction endonucleases, also known as restriction enzymes, are proteins that cut DNA at specific sequences. They can produce either sticky ends or blunt ends when they cleave the DNA.

**Hint:** Remember that sticky ends are overhangs that can easily anneal with complementary DNA, while blunt ends do not have overhangs.

### Step 2: Evaluate the Options
We have four options to evaluate: Hind II, SMART I, EcoRI, and HaeIII.

**Hint:** Look for the specific characteristics of each enzyme regarding the type of ends they produce.

### Step 3: Analyze Each Option
- **Option 1: Hind II**
- Hind II is known to produce blunt ends when it cuts DNA. Therefore, this option is incorrect.

- **Option 2: SMART I**
- SMART I also produces blunt ends. Thus, this option is also incorrect.

- **Option 3: EcoRI**
- EcoRI is a well-known restriction enzyme that produces sticky ends. It recognizes the sequence GAATTC and cuts between G and A, creating overhangs. This option is correct.

- **Option 4: HaeIII**
- HaeIII produces blunt ends as well. Hence, this option is incorrect.

### Step 4: Conclusion
After evaluating all the options, the restriction endonuclease that provides sticky ends of DNA strands is **EcoRI**.

**Final Answer:** EcoRI (Option 3)