DNA Replication, Mutation, Repair

Question 1

Drug that inhibits 50S peptidyltransferase

Answer 1

Chloramphenicol

Question 2

Drug that binds 50S, blocks translocation

Answer 2

Macrolides
Lincomycin
Clindamycin
Streptogramins

Question 3

Drug that binds 30S, prevents attachment of tRNA

Answer 3

Tetracylcines

Question 4

Drug that inhibits PROKARYOTIC RNA polymerase

Answer 4

Rifampin

Question 5

Drug that inhibits PROKARYOTIC topoisomerase

Answer 5

Fluoroquinolones

Question 6

Drug that inhibits PROKARYOTIC dihydrofolate reductase

Answer 6

Trimethoprim

Question 7

Drug that inhibits EUKARYOTIC topoisomerase

Answer 7

Etoposide (anti-cancer)

Question 8

Autoantibody to topoisomerase:

Answer 8

Anti-SCL-70
(diffuse scleroderma)

(crest scleroderma –> anti-centromere antibody)

Question 9

Enzyme that replicates leading strand in PROkaryotes?

Lagging strand?

Answer 9

DNA polymerase III for both

Question 10

Disease resulting from mismatch repair defect

Answer 10

Hereditary nonpolyposis colorectal cancer (HNPCC)

Question 11

Disease resulting from nucleotide exicision repair defect

Answer 11

Xeroderma pigmentosum

*increased risk of skin cancer

Question 12

Disease resulting from mutation of helicase

Answer 12

Bloom syndrome

DNA replication and repair are defective

Question 13

Hypersensitivity to sunlight
Increased cancer risk such as lymphoma, leukemia
Immunodeficiency
Facial anomalies
Infertility, sterility

Answer 13

Bloom syndrome

Helicase mutation –> DNA replication and repair are defective

Question 14

Disease resulting from dsDNA repair defects

Answer 14

ataxia telangiectasia

BRCA1 and BRCA2 mutations

Question 15

IgA deficiency
Cerebellar ataxia, poor smooth pursuit
Elevated AFP
Sensitivity to ionizing radiation

Answer 15

ataxia telangiectasia

Question 16

Replicates LAGGING strand in Eukaryotes

Answer 16

DNA polymerase Alpha (Alpha, lAg rhyme)

Question 17

Synthesizes RNA primer in Eukaryotes

Answer 17

DNA polymerase Alpha

Question 18

Repairs DNA in Eukaryotes

Answer 18

DNA polymerase Beta

Question 19

Replicates mitochondrial DNA in eukaryotes

Answer 19

DNA polymerase Gamma

Question 20

Replicates leading strand DNA in eukaryotes

Answer 20

DNA polymerase Delta

leaD, Delta

Question 21

Thymine dimer repair mechanism:

Answer 21

Nucleotide excision

Question 22

Enzymatic process in base excision:

Answer 22

glycosolases - remove damaged base
endonuclease - nick DNA, remove sugar
DNA polymerase
Ligase

Question 23

Enzymatic process in nucleotide excision:

Answer 23

endonuclease - nick DNA, remove nucleotide
DNA polymerase
Ligase

Question 24

How do mismatch repair enzymes distinguish between old and new strands in prokaryotes?

Answer 24

template’s cytosine and adenine are methylated