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ATM Kinase,”stress-activated kinasestarting point: have very little p53 in our cells (it is a constitutively active gene) b/c cells have specific ubiquitin ligase that targets p53 (Mdm2)directly phosphorylates p53, this phosphorylation stabilizes it. P53 acts as a tetramer (levels starting to rise…have to allow concentration to rise where it can work)have to get Mdm2 out of the way, so ATM also phosphorylates Mdm2, which activates ___ ligase activity (arf?)stabilizing p53 phosphorylation, inactivating ubiquitin ligase to get it out of the way (so p53 levels can increase–>p53 DNA binding protein has different sequences that it binds to w/ different affinities)P53 sites associated with P21cip (stops cell cycle wherever DNA damage takes place, but doesn’t stop damage)activates genes encoding proteins that can fix the damage (once p53 gets to intermediate levels) and if damage fixed, inactivate ATM, shut off kinase, phosphatases come in, dephosphorylate p53, and dephosphorylate Mdm2shuts off P21cip, cell cycle takes off, back to normalif damage ISN’T fixed, p53 levels keep rising

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.ATM Kinase,”stress-activated kinasestarting point: have[…]

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With exposed regions of DNA…,”only have exposed DNA very transiently during transcription and replicationModified guanine will distort double helix, will be enough to activate themRNA polymerase can’t get through them, going to have exposed regions of DNA single stranded DNA activates kinasesKinases have two main targets to phosphorylate:1) P532) checkpoint 1 or 2Going to see:1) stop cell cycle2) activate expression of gene3) if none work

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.With exposed regions of DNA…,”only[…]

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Cytochrome P-450,”enzymes that modify smoked meat compounds(why liver cancer is so prevalent)liver exposed to higher concentration of these compounds than other organs and tissuesIntestinal epithelial cells (exposed to everything that goes through our bodies)cytochrome P-450 convert, guanine forms covalent adduct that can only be repaired by DNA repair enzymes

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.Cytochrome P-450,”enzymes that modify smoked[…]

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Benzo(a)pyrene,”when you ingest it, will have a hard time excreting it b/c not water solubleepoxide intermediate reacts very strongly w/ Guanine (makes covalent bond w/ amino group)no enzyme to cleave bondModified Guanine has distorted structure in DNA double helix–if not removed before DNA replication takes place (p53’s job), it’s distortedDNA polymerase will not pair it with C-it will pair it with A (G-A mismatch)Cell keeps G and converts opposite T to C (which is good, but doesn’t always happen)Some cells throw out modified G and replace it with T. Original G on DNA sequence, converted to T(A-T basepair

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.Benzo(a)pyrene,”when you ingest it, will[…]

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