Exam 2

Question 1

Cross-linking agents:

Answer 1

Nitrogen mustard
Cisplatin
Mitomycin C
Carmustine

Question 2

Alkylating agents

Answer 2

Dimethyl sulfate (DMS)
Methyl methanesulfonate (MMS)

Question 3

Intercalating agent

Answer 3

Thalidomide

Question 4

UV radiation causes

Answer 4

Pyrimidine dimers

Question 5

Ionizing radiation causes…

Answer 5

Strand breaks
Chemical mods of bases
DNA protein crosslinks

Question 6

Non-ionizing radiation causes…

Answer 6

Thymine dimers

Question 7

Spontaneous DNA damage causes…

Answer 7

Depurination

Deamination

Question 8

Nucleotide excision repair

• what type of damage does it fix?
• enzymes involved?
• associated disorder?

Answer 8

• fixes chemical addicted that distort DNA (pyrimidine dimers, BPDE-guanine adducts, cisplatin adducts)
• enzymes are NER protein complex, DNA poly, DNA ligase
• xeroderma pigmentosum

Question 9

Mismatch excision repair

• damage type?
• enzymes?
• disease associated?

Answer 9

• mismatched base in daughter strand
• MER complex, helicase/endonuclease, DNA poly, DNA ligase
• hereditary nonpolyposis colorectal cancers

Question 10

Homologous recombination associated disorder

Answer 10

BRCA1/2 breast cancer

Question 11

Transcription coupled repair associated disorder

Answer 11

Cockayne syndrome (also associated with nucleotide excision repair)

Question 12

Cockayne’s syndrome

Answer 12

Defect in transcription coupled repair
Growth retardation, skeletal abnormalities, sensitivity to sunlight
RNA polymerase is permanently stalled at sites of damage in important genes

Question 13

Modifications on Lysine residues

Answer 13

Ubiquitination
SUMOylation
Acetylation
Methylation

Question 14

Modifications on Serine or threonine

Answer 14

Phosphorylation

Question 15

Duchenne Muscular dystrophy DNA mutation type

Answer 15

Frameshift

Question 16

Sickle cell anemia DNA mutation type

Answer 16

Missense

Question 17

Streptomycin

Answer 17

Binds to the 30S subunit to disrupt initiation of translation; interferes with binding fmet-tRNA, blocks association of 30S with 50S

Question 18

Shiga toxin

Ricin

Answer 18

Binds to the 60S subunit to disrupt elongation by blocking entry of aminoacyl-tRNA to ribosomal complex

Question 19

Clindamycin

Answer 19

Binds to the 50S subunit to disrupt translocation of the ribosome

Question 20

Erythromycin

Answer 20

Binds to the 50S subunit to disrupt translocation of the ribosome; commonly used o treat pertussis

Question 21

Tetracyclines

Answer 21

Bind to the 30S subunit to disrupt elongation by blocking entry of aminoacyl-tRNA to ribosomal complex

Question 22

Peptidyl transferase activity is housed where?

Answer 22

Large subunits of ribosomes

Question 23

Diphtheria toxin

Answer 23

Inactivates eEF2-GTP and inhibits elongation, interferes with ribosomal translocation

Question 24

Chloramphenicol

Answer 24

Inhibits peptidyl transferase (prok./mitoc.)

Question 25

Cycloheximide

Answer 25

inhibits eukaryotic peptidyl transferase

Question 26

Puromycin

Answer 26

causes premature chain termination (prok/euk). Resembles the 3’ end of the aminoacyl-tRNA

Question 27

Protein Post-translational modifications

Answer 27

Acetylation: on Lys
Glycosylation: O on Ser/Thr; N on Asn/Gln
Phosphorylation: on Ser, Tyr, Thr (also Asp and His)
Disulfide bonds: on Cys