Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight, and mutations to the DNA in their skin cells are left uncorrected. Why are the mutations not corrected in individuals with this disorder?
A) The disorder makes cells unable to replicate DNA.
B) The disorder causes mitosis to stop during metaphase.
C) The disorder makes cells unable to form chromosomes.
D) The disorder causes cells to be unable to repair thymine dimers.

Question

Quizplus · Accepted Answer

Xeroderma pigmentosum is caused by a defect in the nucleotide excision repair pathway, which is responsible for correcting DNA damage including thymine dimers caused by UV radiation. Without the ability to repair thymine dimers, mutations in the skin cells are left uncorrected.

Individuals with the Disorder Xeroderma Pigmentosum Are Hypersensitive to Sunlight