Ultraviolet (UV) radiation is mutagenic.

How do UV-induced DNA lesions lead to mutation?

Verified step by step guidance

1. Understand that UV radiation can cause DNA damage, primarily by inducing the formation of pyrimidine dimers, which are covalent linkages between adjacent pyrimidine bases (usually thymine) on the same DNA strand.
2. Recognize that these pyrimidine dimers distort the DNA helix, interfering with normal DNA replication and transcription processes.
3. Consider that during DNA replication, the DNA polymerase may encounter these dimers and incorporate incorrect bases opposite the damaged site, leading to mutations.
4. Note that if the DNA damage is not repaired before replication, the incorrect bases can become permanent mutations in the DNA sequence.
5. Explore the cellular repair mechanisms, such as nucleotide excision repair, which can remove these dimers and restore the DNA to its original sequence, preventing mutations if the repair occurs before replication.

Key Concepts

UV Radiation and DNA Damage

Ultraviolet (UV) radiation can cause direct damage to DNA by inducing the formation of pyrimidine dimers, primarily thymine dimers. These dimers distort the DNA helix, leading to replication errors if not repaired. Understanding this mechanism is crucial for grasping how UV exposure can lead to mutations.

DNA Repair Mechanisms

Cells have evolved several DNA repair mechanisms, such as nucleotide excision repair (NER), to correct UV-induced lesions. NER recognizes and removes damaged sections of DNA, allowing for accurate repair. If these repair processes fail or are overwhelmed, the unrepaired lesions can result in permanent mutations.

Mutation and Its Consequences

A mutation is a change in the DNA sequence that can alter gene function and potentially lead to various outcomes, including cancer. UV-induced mutations often occur in critical genes that regulate cell growth and division, making it essential to understand how these mutations can contribute to tumorigenesis and other genetic disorders.