Genetic engineering is possible because

Options

A. DNA can be cut at specific site by endonucleases like DNAase
B. Restriction endonucleases purified from bacteria can be used in vitro
C. The phenomenon of transduction in bacteria is well understood
D. DNA can be seen by electron microsocpe

Answer

**Step-by-Step Solution:**

1. **Understanding Genetic Engineering**: Genetic engineering involves manipulating an organism's DNA to isolate and insert specific genes. This process is fundamental in biotechnology for applications like gene therapy, cloning, and the production of genetically modified organisms (GMOs).

2. **Identifying the Gene of Interest**: The first step in genetic engineering is identifying and isolating the desired gene (gene of interest) from an organism. This gene can often be found in plasmids or other genetic material from microorganisms.

3. **Cutting DNA with Restriction Endonucleases**: To isolate the gene of interest, specific enzymes called restriction endonucleases are used. These enzymes can cut DNA at specific sites, allowing for the precise removal of the gene of interest from the rest of the DNA.

4. **Preparing the Host DNA**: After isolating the gene of interest, the next step is to prepare the host DNA (the DNA of the organism into which the gene will be inserted). This also requires cutting the host DNA at specific sites using the same restriction endonucleases.

5. **Inserting the Gene of Interest**: Once both the gene of interest and the host DNA are cut, the gene can be inserted into the host DNA. This is typically done using another enzyme called DNA ligase, which joins the gene of interest with the host DNA, creating a recombinant DNA molecule.

6. **Conclusion**: The ability to cut DNA at specific sites using restriction endonucleases is a crucial aspect of genetic engineering. This specificity allows scientists to manipulate genes accurately, making genetic engineering possible.

**Correct Answer**: The correct option is that genetic engineering is possible because "restriction endonucleases purified from bacteria can be used in vitro."

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