DNA Replication/Repair

Question 1

Direction of Replication/Writing

Answer 1

Always 5’ to 3’

Question 2

Euk DNA Pol alpha

Answer 2

Complex, replicates lagging strand and synthesizes RNA primer

Question 3

Euk DNA Pol beta and epsilon

Answer 3

Repair DNA

Question 4

DNA Pol gamma

Answer 4

Replicates mitochondrial DNA

Question 5

Euk DNA Pol delta

Answer 5

Synthesizes leading strand

Question 6

Prok DNA Pol III

Answer 6

Elongates leading strand and lagging strand (until it hits primer of preceding fragment) and proofreads with 3’ to 5’ exonuclease

Question 7

Prok DNA Pol I

Answer 7

Degrades RNA primer and replaces it with DNA (5’ to 3’ exonuclease)

Question 8

Xeroderma Pigmentosa

Answer 8

AR defect in nucleotide excision repair, so you can’t repair damaged single strand oligonucleotides like thymine dimers. So can’t go out in UV light - dry skin/melanoma

Question 9

Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

Answer 9

Defect in mismatch repair leading to colon cancer and other stuff

Question 10

Ataxia Telangiectasia

Answer 10

Defect in nonhomologous end joining ds repair, so sensitized to ionizing radiation. Get cerebellar gait ataxia/poor pursuit of eyes and immunodeficiency

Question 11

Bloom’s Syndrome

Answer 11

Hypersensitivity to sunlight with leukemia/lymphoma predisposition. Age of onset 25 yo

Question 12

BRCA

Answer 12

ds DNA break repair defect