a 27-year-old Caucasian woman with red hair and fair skin spent 4 hours on the catamaran tour without applying sunscreen to her skin. Which of the following is most likely to happen within the patient’s skin cells as a result of this exposure?A. Double-stranded breaks undergo end-joining repairB. Adjacent purine bases for a covalent bondC. Specific glycosylases remove deaminated basesD. Adenine residues of the undamaged bases undergo methylationE. Specific endonucleases nick the damaged DNA strand66. A 30-year-old woman has a lipid profile done on a routine health screening and has a blood cholesterol level of 400 mg/dL with a normal serum triglyceride level. Her father suffered a myocardial infarction at age 35 and her paternal grandfather suffered a fatal heart attack at age 38. DNA samples are obtained from family members. Southern blot of restriction fragments from a region of the LDL receptor gene shows the following23 Gen-1.docxpatternA. The mutation is probably located in the 12kb bandB. The mutation is probably located in the 10kb bandC. The patient’s son most likely carries the mutationD. The patient’s brother most likely carries the mutationE. The disease is transmitted in an X-linked fashion67. A 5-year-old Caucasian boy is brought to the pediatrician because of recurrent skin lesions on his face and upper extremities when exposed to sunlight. Skin biopsy reveals basal cell carcinoma. Xeroderma pigmentosum is suspected as a causative diagnosis. Which of the following enzymes is most likely nonfunctional if this is the correct diagnosis?A. 3′? 5′ exonucleaseB. EndonucleaseC. TopoisomeraseD. DNA ligaseE. Helicase68. A 16-year-old teenage girl presents to clinic because she has not yet achieved menarche. Physical examination reveals a short young lady with webbed neck