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Exposure of UV radiations causes...

Exposure of UV radiations causes

A

Formation of thymine dimers

B

Addition of base pairs

C

Deletion of base pairs

D

Methylation of bases.

Text Solution

AI Generated Solution

The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding UV Radiation**: Ultraviolet (UV) radiation is a type of electromagnetic radiation that can cause damage to living organisms, particularly at the molecular level. 2. **Impact on DNA**: When DNA is exposed to UV radiation, it can lead to the formation of specific types of damage. One of the most common forms of damage is the formation of thymine dimers. 3. **Formation of Thymine Dimers**: Thymine dimers occur when two adjacent thymine bases on a DNA strand bond together through a covalent linkage. This abnormal bonding distorts the DNA structure. 4. **Consequences of Thymine Dimers**: The presence of thymine dimers can interfere with DNA replication. During the replication process, the DNA polymerase may skip over these dimers, leading to mutations in the DNA sequence. 5. **Repair Mechanisms**: Cells have mechanisms to repair DNA damage, including thymine dimers. However, if the damage is extensive or the repair mechanisms fail, it can result in permanent mutations. 6. **Conclusion**: Therefore, the exposure of UV radiation primarily causes the formation of thymine dimers in DNA, which can lead to mutations. **Final Answer**: Exposure of UV radiation causes the formation of thymine dimers. ---
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