Term 'Restriction' in Restriction endonuclease enzyme refers to

Options

A. Cleaving of phosphodiester bond in DNA by the enzyme
B. Cutting of DNA at specific position only
C. Preventing of bacteriophage multiplicatioin in bacteria
D. Cutting each of two strands of DNA at specific points in sugar phosphate backbone

Answer

**Step-by-Step Solution:**

1. **Understanding Restriction Endonucleases**:
- Restriction endonucleases, also known as restriction enzymes, are proteins that can cut DNA at specific sequences. They are crucial tools in biotechnology, particularly in recombinant DNA technology.

2. **Definition of 'Restriction'**:
- The term 'restriction' refers to the ability of these enzymes to recognize specific sequences of nucleotides in the DNA and cut the DNA at those sites. This is a form of 'restriction' because it limits the places where the DNA can be cut.

3. **Mechanism of Action**:
- These enzymes identify specific sequences (known as restriction sites) within the DNA molecule. Once they locate these sites, they cleave the phosphodiester bonds in the sugar-phosphate backbone of the DNA, resulting in the separation of the two strands.

4. **Importance in Biotechnology**:
- The cutting of DNA at specific sites allows scientists to manipulate genes, insert new DNA sequences, and create recombinant DNA. This is essential for cloning, gene therapy, and various genetic engineering applications.

5. **Conclusion**:
- Therefore, the term 'restriction' in restriction endonucleases refers to the cutting of DNA at specific locations in the sugar-phosphate backbone, allowing for precise manipulation of genetic material.