A gene whose expression helps to identify transformed cell is known as

Options

A. Selectable marker
B. Vector
C. Plasmid
D. Structural gene

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of a gene that helps identify transformed cells in the context of biotechnology.

2. **Identifying Key Terms**: The key terms in the question are "gene," "expression," and "identify transformed cell." This indicates that we are looking for a specific type of gene used in genetic engineering.

3. **Analyzing the Options**:
- **Selectable Marker**: This is a gene that allows for the identification of cells that have been successfully transformed with foreign DNA. It typically provides resistance to antibiotics or other selection agents.
- **Vector**: This is a vehicle (like a plasmid) used to transfer genetic material into a host cell but is not a gene itself.
- **Plasmid**: This is a type of vector, a small circular DNA molecule, but again, it is not a gene.
- **Structural Gene**: This type of gene codes for proteins or RNA but does not specifically aid in identifying transformed cells.

4. **Conclusion**: Based on the definitions and functions of the options provided, the correct answer is **Selectable Marker**. This gene is specifically used to differentiate between transformed and non-transformed cells after the genetic engineering process.

5. **Final Answer**: A gene whose expression helps to identify transformed cells is known as a **Selectable Marker**.

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