Which of the radiations induces the formation of thymine dimers in DNA , which interfere with its replication ?

Options

A. UV radiations
B. X - rays
C. Gamma rays
D. Infra red light

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which type of radiation induces the formation of thymine dimers in DNA, leading to interference with DNA replication.

2. **Identifying Thymine Dimers**: Thymine dimers occur when two adjacent thymine bases in DNA covalently bond together. This process is significant because it can disrupt the normal base pairing and replication of DNA.

3. **Types of Radiation**: The options provided are:
- a. UV radiation
- b. X-rays
- c. Gamma rays
- d. Infrared light

4. **Analyzing Each Option**:
- **UV Radiation**: This type of radiation is known to cause the formation of thymine dimers by inducing covalent bonds between adjacent thymine bases when DNA is exposed to UV light.
- **X-rays**: These are high-energy electromagnetic waves that primarily cause breaks in the DNA strands rather than forming dimers.
- **Gamma Rays**: Similar to X-rays, gamma rays can cause DNA damage but do not specifically induce thymine dimers.
- **Infrared Light**: This type of radiation does not have enough energy to cause DNA damage or the formation of thymine dimers.

5. **Conclusion**: Based on the analysis, the radiation that induces the formation of thymine dimers in DNA, which interferes with its replication, is **UV radiation**.

6. **Final Answer**: The correct answer is **a. UV radiation**.

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