Which colour would you find in DNA strands after stain- ing with Ethidium bromide in the presence of UV light ?

Options

A. Red
B. Green
C. Orange
D. Yellow

Answer

**Step-by-Step Solution:**

1. **Understanding the Process**: The question involves the staining of DNA strands with Ethidium bromide and observing the color under UV light. Ethidium bromide is a common fluorescent dye used in molecular biology.

2. **Staining with Ethidium Bromide**: When DNA is stained with Ethidium bromide, the dye intercalates between the bases of the DNA. This means that the dye inserts itself into the DNA structure.

3. **Exposure to UV Light**: After staining, the DNA is exposed to ultraviolet (UV) light. Ethidium bromide is known to fluoresce when exposed to UV light.

4. **Identifying the Color**: The fluorescence emitted by Ethidium bromide when exposed to UV light is typically orange. This is a key characteristic of the dye.

5. **Choosing the Correct Option**: Given the options (red, green, orange, yellow), the correct answer is orange, as this is the color observed when DNA stained with Ethidium bromide is viewed under UV light.

**Final Answer**: The color you would find in DNA strands after staining with Ethidium bromide in the presence of UV light is **orange**.

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