When a piece of DNA is digested with Eco RI, what kind of ends are created ?

Options

A. Blunt ends
B. Flush ends
C. Cohesive ends
D. Non-staggered ends

Answer

**Step-by-Step Solution:**

1. **Understanding Eco RI**: Eco RI is a type of restriction endonuclease enzyme that recognizes specific sequences in DNA and cuts it at those sites.

2. **Recognition Sequence**: The recognition sequence for Eco RI is a palindrome, which means it reads the same forwards and backwards. The specific sequence is GAA TTC.

3. **Cutting Mechanism**: Eco RI cuts the DNA between the bases guanine (G) and adenine (A) on both strands of the DNA. This action creates a staggered cut.

4. **Type of Ends Created**: The staggered cut results in the formation of "sticky ends" or "cohesive ends." These ends have overhanging sequences that can easily bind to complementary DNA fragments.

5. **Comparison with Other Cuts**: It’s important to note that not all restriction enzymes create sticky ends. Some create blunt ends, which do not have overhangs. However, Eco RI specifically produces sticky ends due to its staggered cutting action.

6. **Conclusion**: Therefore, when a piece of DNA is digested with Eco RI, it creates sticky ends.

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