The mutant strain of yeast couldn't repair its own DNA when exposed to the sun. This feature makes this strain an ideal candidate for use in testing the effectiveness of UV protectants.
In the context of the skin cancer lab, a mutant strain of yeast was utilized to test the effectiveness of a UV protectant. The mutant yeast in question (A) does not possess the ability to repair its own DNA when exposed to sunlight. Exposure to the UV rays from the sun causes damage to the DNA within the yeast cells, a situation that mimics DNA damage in mammalian cells inflicted by the sun's radiation. Using this mutant yeast strain, a controlled UV exposure experiment can be designed to study the efficacy of different UV protectants. Upon exposure to UV radiation, if the DNA of the yeast fails to repair itself, it indicates that the UV protectant being tested is ineffective.
Learn more about UV protectants