How does light (uv radiation) effect bacterial growth?
By causing change in the DNA structure.
Non-ionizing radiation, such as ultraviolet
(UV) light, exerts its mutagenic effect by exciting electrons in molecules. Theexcitation of electrons in DNA molecules often results in the formation of extrabonds between adjacent pyrimidines (specifically thymine) in DNA. When twopyrimidines are bound together in this way, it is called a pyrimidine dimer.
These dimers often change the shape of the DNA in the cell and can cause problems during replication. The cell often tries to repair pyrimidine dimers before replication, but the repair mechanism can also lead to mutations as well.