In biolistic or gene gun method DNA is coated with__________ .

Answer

**Step-by-Step Solution:**

1. **Understanding the Biolistic or Gene Gun Method**: The biolistic or gene gun method is a technique used for the transformation of cells. It involves delivering DNA into cells using high-velocity microprojectiles.

2. **Role of Vector DNA**: In this method, a vector plasmid DNA is utilized, which contains the gene of interest that needs to be transferred into the host cell. This vector DNA is circular and exists independently of the host cell's chromosomal DNA.

3. **Transformation Process**: Transformation refers to the process of introducing recombinant DNA (the vector DNA containing the gene of interest) into the host cell. This is essential for creating recombinant cells that can express the desired gene.

4. **Challenges with Cell Walls**: Most host cell walls are impermeable to foreign DNA, which makes it difficult for the vector DNA to enter the cells. Therefore, alternative methods are required to facilitate the entry of DNA into the host cells.

5. **Mechanism of the Gene Gun**: In the gene gun method, the recombinant DNA is coated onto tiny metal particles, usually made of gold or tungsten. These particles are then accelerated and shot into the target cells.

6. **Outcome of the Process**: When these metal particles penetrate the host cell, they may deliver the recombinant DNA, resulting in the transformation of the host cell into a recombinant cell that can express the gene of interest.

7. **Final Answer**: In the biolistic or gene gun method, DNA is coated with **gold or tungsten**.

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