What limited protection do cells have against the damaging effects of UV radiation?

Many factors determine a cell's limited protection against damaging effects of Ultraviolet (UV) radiation.

The amount of time a cell is exposed is one eminent factor that blocks radiation from reaching cells. (Think: the plastic from sunglasses shields UV light from damaging the human eye.)

Certain types of cells are more resistant to UV light that vegetative cells. DNA of endospores is protected by small, acid-soluble proteins that bind to DNA and alter its conformation, protecting it from photochemical damage. In addition, a unique spore photo-product is generated by UV light in endospores that functions in enzymatic repair of damaged DNA during endospore germination.