DNA or RNA segment tagged with a radioactive molecule is called

Options

A. vector
B. probe
C. clone
D. plasmid

Answer

To solve the question "DNA or RNA segment tagged with a radioactive molecule is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Options**: The question provides four options: vector, probe, clone, and plasmid. We need to analyze each option to determine which one correctly describes a DNA or RNA segment tagged with a radioactive molecule.

2. **Define Each Term**:
- **Vector**: A vector is a DNA molecule used to carry foreign genetic material into another cell. It is not specifically related to radioactive tagging.
- **Probe**: A probe is typically a single-stranded DNA or RNA that is used to detect complementary sequences in a sample. Probes are often labeled with radioactive molecules to make them easier to detect.
- **Clone**: A clone refers to an identical copy of a gene, cell, or organism produced through artificial means. This term does not relate to radioactive tagging.
- **Plasmid**: A plasmid is an extra-chromosomal DNA found in bacteria that can carry genes, but it does not specifically refer to a radioactive tag.

3. **Identify the Correct Answer**: Based on the definitions, the term that best fits the description of a DNA or RNA segment tagged with a radioactive molecule is **probe**. Probes are specifically designed for detection and are often labeled with radioactive substances.

4. **Conclusion**: Therefore, the answer to the question is that a DNA or RNA segment tagged with a radioactive molecule is called a **probe**.