4 If skin cells from an individual with Xeroderma pigmentosu

4) If skin cells from an individual with Xeroderma pigmentosum were exposed to UV light and incubated with radiolabeled nucleotides and washed, you would find that _________ because _____________.

A) The cells contain lots of radioactive DNA, individuals with Xeroderma pigmentosum have defects in mismatch repair.

B) The cells contain minimal amounts of radioactive DNA, individuals with Xeroderma pigmentosum have defects in mismatch repair.

C) The cells contain minimal amounts of radioactive DNA, individuals with Xeroderma pigmentosum have defects in nucleotide excision repair.

D) The cells contain minimal amounts of radioactive DNA, individuals with Xeroderma pigmentosum have defects in DNA replication.

E) The cells contain lots of radioactive DNA, individuals with Xeroderma pigmentosum experience more UV-induced DNA damage.

Solution

The answer is: C. The cells contain minimal amounts of radioactive DNA, individuals with Xeroderma pigmentosum have defects in nucleotide excision repair.

If skin cells from an individual with Xeroderma pigmentosum were exposed to UV light and incubated with radiolabeled nucleotides and washed, you would find that the cells contain minimal amounts of radioactive DNA, because individuals with Xeroderma pigmentosum have defects in nucleotide excision repair.

Skin cells with Xeroderma pigmentosum cannot repair cells damaged by UV rays as it has defects in nucleotide excision repair mechanisms.