27.What are some variations in animal studies? Nature of the carcinogen, rat strain, diet, fibre differences, food amount intake, design. 28.What did a study done on cancer in twins conclude to? Stomach cancer has a 30% heritable cause and a ratio of 7/3 of environment to heritable causes showing a strong influence on the environmental factor. The absolute risk was higher for identical twins(15%) versus fraternal twins(6%). In conclusion, only 1% were unmistakably hereditary. 29.What percentage of cancers are caused by environmental factors? 70-90%. 30.What are some environmental causes? Viruses, Alcohol, Smoking, sun exposure, diets, radiation, soil, carcinogen exposure. 31.Which case showed a clear associated with occupation and cancer? Chimney Sweeps. 32.Which cancer was at a very high rate in chimney sweeps? Testicular Cancer. 33.What are created after dehydration of cooked meat on a barbeque? Polycyclic Aromatic Hydrocarbons, which are known carcinogens. 34.Where are PAHs also found? Engine exhaust, tobacco smoke and some cooked meats. 35.Why are PAHs dangerous? They interact with DNA. 36.What is another end product of heat? Heterocyclic Amines(PhIP) 37.What is the process in which PhIP fit in DNA causing a disturbance? 38.Which foods contain PhIPs in the greatest amount? Beef, Finfish and Chicken. 39.Why is it difficult to categorize one method of cooking as unhealthy? Because individuals metabolize substances at differing rates depending on their chemical/genetic make up. 40.Which family of enzymes alters molecules in order to remove them from the body? Cytochrome P450.
41.How does Cytochrome P450 work? It oxidizes the molecule to make it more water soluble and thus easier to expel from the body. 42.What molecules does Cytochrome P450 specifically target? Heterocyclic amines and polycyclic aromatic hydrocarbons. 43.Which foods contribute most as precursors to PAHs? Cereals and Oils/Fats. 44.Why are these foods so high in their PAH contribution? They are eaten in very large consumption compared to other foods. 45.Which substance has been found in starchy foods to cause cancer in rodents? 46.What is acrylamide specifically when it comes to adverse effects? Neurotoxin. 47.How is acrylamide formed? Asparagine(amino acid) when attached and heated to glucose will give acrylamide as a product.
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