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24 Cards in this Set
- Front
- Back
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Process of an action potential?
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The inside of the cell is negative, sodium rushes in, after the peak, cell is too positive and K+ goes out the cell to equilibriate.
After the nerve impulse passes, the sodium potassium pump with ATP restore back to resting state with pumping out Na+ and pumping in K+ |
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How does DDT work on the action potential?
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DDT prolongs the actions potential after it hits its peak
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What's the structure of DDT and DDE???
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p. 138
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How is DDT metabolized to DDE?
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DDT dehydrochlorinase enzyme in resistant insects. Dehydrochlorinases
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What is a negative temperature coefficient and DDT has this!?
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More effective at low temperatures than at high temperatures. Will kill in the cool morning rather and no effect during hot afternoon.
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How does DDT help control malaria?
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Killed off the mosquitos that transmitted malaria
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Why did resistance to DDT develop so quickly?
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Due to the dehydrochlorinase enzyme in some insects and nerve insensitivity. "knockdown resistance" or kdr factor, so many killed off only resistant strains left and they proliferate
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Why was DDT restricted in use and banned?
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It had chronic tox as carcinogen, appears in breast milk. It also had environmental impacts with thinning of bird egg shells. Some fish died by direct contact
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Why was the DDT persistence a problem?
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DDT was resistant to light, heat, and most microorganisms and enzymes. It remained in the environment and its loss from soil is very slow. It would contaminate ground water and result in bioaccumulation
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How does the DDT analog METHOXYCHLOR compare?
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It's more expensive! It works shittier and it doesn't persist long.Nobody uses this **** that much
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What plant does pyrethrum come from and which countries are most important in production and extraction?
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Daisy- chrysanthemum cinerariaefolium. It's production and extraction is mainly in KENYA, TANZANIA, RWANDA AND TASMANIA.
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How many ester components to pyrethrin are there?
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6.
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Which ester components are the most potent and how are they important for kill and knockdown?
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Pyrethrin I and Pyrethrin II. 1 is for kill and 2 is for knockdown
Pyrethrin I = chyrsanthemic acid 35% in pyrethrum Pyrethrin II= pyrethric acid, 32% in pyrethrum Other properties--> photolabile (likely to change), metabolized quickly |
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How many isomers of chrysanthemic acid are there? How many are made naturally?
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4 isomers, with 1 isomer naturally made (1R,cis and 1R trans)???
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What is a problem with Chrysanthemates used in agriculture?
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It's unstable in light and air
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How is the chrysantehmates' photoinstability overcome?
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Added antioxidant or photostabilizer or remove photolabile groups with more stable substituents
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What are the chrysanthemates? What are the stabilized acid moieties? What does the cyano group do?
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Chrysanthemates= allethrin, tetramethrin, resmethrin
stabilized acid moieties= (without cyano) permethrin, tefluthrin (with cyano) cypermethrin and deltamethrin The cyano group provides greater potency |
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Which of the pyrethrins is the most potent?
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DELTAMETHRIN
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What is the mode of action of pyrethroids? What is knockdown potency correlated with?
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Rapid knockdown- quickly penetrate and enter the nervous system. also act as repellants
More polar, more knockdown potency |
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Why are pyrethrin generally regarded as the safest insecticide?
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LD50 for rat is 820-1500 mg/kg with tremors and muscular paralysis
No tissue damage at 1000-5000ppm in diet Allergenic component to humans removed |
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What kind of isomers are more toxic in pyrethroids?
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CIS ISOMERS are more toxic than trans
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What is an environmental problem associated with pyrethroids?
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Fish are very sensitive (but they don't leach from soil too well and it's bird resistant)
Biodegradable and non persistent |
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What is a synergist and how does it work? What is the most important synergist for pyrethroids? What is the ratio for synergist to pyrethroid?
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Makes the compound more potent or effective. PIPERONYL BUTOXIDE the most important synergist.
Competitive substrate for detoxification enzyme, so the pyrethroid stays toxic for longer The ratio is 8 parts synergist to 1 part pyrethroid |
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What's another Sodium channel insecticide?
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INDOXACARB!!
it acts on the sodium channel but it has a different target? broad selectivity no cross resistance with pyrethroids |
