Question

To maximize the number of thymine dimer mutations following UV exposure, should you keep human cells in tissue culture in the dark, in the light, or does it matter at all?

Answer 1

It doesn't matter at all.

Step-by-step explanation:

Thymine dimers are corrected by DNA photolyases. The chromophore of these enzymes absorbs the energy of light to fix the dimers. However, the placental mammals such as human do not have the DNA photolyases to correct the dimers formed by exposure to UV radiations.

Hence, keeping the UV exposed cells in light or dark would not have any effect on the number of thymine dimers produced by UV exposure of a human cell.