Molecular 1

Question 1

Mechanism of UV damage to DNA?
Repair enzyme?
Disease resulting from deficiency of the repair enzyme?

Answer 1

thymine dimerization..
U-V specific endonuclease.
xeroderma pigmentosum.

Question 2

what provides the (+) charge of histones?

(-) charge of DNA?

Answer 2

Lys, Arg

Phospate

Question 3

What drug inhibits ribonucleotide reductase?

Answer 3

Hydroxyurea. (Ribonucleotide reductase catalyzes UMP -> dUMP)

Question 4

Drug that inhibits dihydrofolate reductase

Answer 4

MTX (eukaryotes)

Trimethoprim (prokaryotes)

Question 5

drug that inhibits thymidilate synthase

Answer 5

5-flourouracil, an anti-cancer drug

Question 6

drug that inhibits Inosine Monophosphate dehydrogenase

Answer 6

mycophenolate, an immunosuppressant used post-transplant

Question 7

features of orotic aciduria caused by defect in pyrimidine synthesis?
Tx?

Answer 7

megaloblastic anemia (unresponsive to B12 or folate), failure to thrive. (no hyperammonemia, as would be seen in OTC deficiency). 
Tx: oral uridine

Question 8

What are the features of xeroderma pigmentosum?

Answer 8

Highly susceptible to cancers. Photosensitivity, poikiloderma, hyperpigmentation in sun-exposed areas.

Question 9

What are the uses of hydroxyurea?

Answer 9

for polycythemia vera, essential thrombocytopenia