Molecular (Kaplan) 1 Flashcards
What class of antibiotics targets bacterial gyrase (topoisomerase II)? Provide examples.
Quinolones:
Ciprofloxacin, Moxifloxacin, Levofloxacin
(Novobiocin, which is used to differentiate Staph. epidermidis (susceptible) from S. saprophyticus, also targets bacterial DNA gyrase.)
What drugs target eukaryotic topoisomerase II?
Etoposide, teniposide (ALL)
Which DNA polymerase replicates mitochondrial DNA?
gamma
What kinds of bacteria are quinolones most effective against?
gram(-) aerobes, such as gonorrhea and UTIs
What is Zidovudine (azidothymidine, AZT)?
nucleoside analog reverse transcriptase inhibitor
Lynch syndrome (HNPCC) results from a defect in _______-repair genes.
mismatch
What is the defective enzyme in Xeroderma Pigmentosum and what does it normally do?
excision endonuclease; repairs thymidine dimers
What is the role of p53 or Rb in the cell cycle?
prevent cell from entering S-phase before mutations are repaired
What is the other role of p53?
induce apoptosis in cell w/ mutated genome
What are the 2 mismatch repair genes implicated in HNPCC?
MLH1 and MSH2
What is microsatellite instability and what does it indicate?
Variable numbers of di- and tri-nucleotide repeats between cells w/in an individual. Indicates defect in mismatch repair genes.
Cytosine deamination, what’s that all about? What 2 enzymes cleave out this defect?
Spontaneously or due to heat, C may become deaminated to U. 2 enzymes, uracil glycosylase and apyrimidinic (AP) endonuclease, will cleave out the defect. DNA polymerase and DNA ligase will then fill in the gap and seal it, respectively.
What direction is DNA read in?
3’–>5’
What direction is DNA or RNA synthesized in?
5’ –> 3’
What direction is mRNA read in by the ribosome?
5’ –> 3’
