An 18-year-old lifeguard sits in the sun all day wearing only a swimsuit, a t-shirt, and sunglasses. As UV-B rays damage the DNA of the squamous cells on the lifeguard's ear, which of the following steps is the first to occur?
- BAX gene transcription is activated
- Cyclin/CDK complex is inhibited
- GADD45 transcription is stimulated
- p21 transcription is stimulated
- p53 degradation is halted and the enzyme is modified