Biology - Biology 19:57 Nucleic acids Nucleotide polymers...

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Unformatted text preview: Biology 19:57 Nucleic acids Nucleotide polymers that carry information o Breakdown (monomers of r/DNA) Deoxyribose sugar (no OH group) Phosphate group Base: Adenine Thymine Guanine Cytosine o Free carbon on the ribose bonds with the phosphate group creating a sugar-phosphate backbone o Hydrogen bonding between bases ATP is adenesine tri Phosphate o Adenine base + Ribose + 3 Phosphate o Adenine plays a very important role in signaling and other things Prions Proteinaceous infection Particles Discovered by Stanley Prusiner o Infectivity follows protein No matter how much he purified, he was left with protein o Trans species effect o Infectious agent not affected by UV or nucleases o Resistant to proteases but can be digested All prion diseases affect the whole brain but hone in on certain parts more than others o Kuru : cerebellum o CJD : cerebral Cortex o Scrapie : brain stem Structural differences between normal and pathogenic prions o Protein PrP Common body protein in sheeps, cows, apes, ect When PrP was isolated form healthy brain, it could easily be digested All alpha-helix Function still unknown o PrP(sc) The scrapie prion (PrPsc) could not be digested It was folded wrong Some beta-sheets Can force normal proteins to refold in different configuration Very hard to kill Pathogenisis of prion Diseases o PrP(sc) can come in contact with a PrP and change its shape o You then have exponential growth of PrP(sc) Evidence that PrP mutations cause Transmissible Spongiform Encephalopathy (TSE) o All TSEs have PrP mutations o Over expressing a human TSE prion in a mouse causes TSE o If you knock out PrP in mice, they cannot be infected with TSE Prion Diseases Scrapie o Disease in sheep o Seep got itchy and scraped themselves, lost fur, lost weight, died o Brain looked normal but if you did sectionals and looked under a microscope the brain had little tiny holes Spongiform encephalopathy Kuru o Epidemic in new guinea in the 50s Between 1950 75 Killed 3000 women and children Starts with lack of coordination, mood swings, panic attacks, death No cure Carleton Gadjusek aimed to find a cure Found no evidence of infectious agent No bacteria No cerebral inflammation No toxic substances in diet Soon realized that part of funeral traditions for the indigenous people (canabalism) was the cause Women and children ate the brains of the dead After Australia outlawed brain eating and incidences of kuru dropped dramatically Found that if you mashed up the brain of a kuru victim and inject it...
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Biology - Biology 19:57 Nucleic acids Nucleotide polymers...

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