What happens to the DNA in the bacterium Serratia marcescens when it is exposed to ultraviolet radiation?

Actually the organism is not relvant. UV exposition of DNA usually result in thymidine dimers. That is, adjacent thymines and also cytosines and thymines form bond which disrupt the normal function of DNA (that is transcription, replication etc.).

Perhaps the question was asked in light of the fact that <I>Serratia marcescens</I> is a common hospital-acquired pathogen. Does the question relate to a school project on sterilization methods in hospital settings?

Cells (be they pro- or eukaryotic) have repair mechanisms that deal with “bulky lesions” such as thymidine dimmers.

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