Figure: 20-01 Title: Poison hemlock Caption: Poison hemlock (Conium maculatum), the plant from which the hemlock taken by Socrates was probably prepared from the unripe but full-grown fruit of this plant. The principal alkaloid in poison hemlock is coniine. Notes: Keywords: hemlock, poison, plant, coniine

Figure: 20-01-03un Title: The hydrolysis of amides Caption: Strong acids and bases catalyze the hydrolysis of amides, including proteins. Notes: Keywords: acid, base, amide, hydrolysis, protein

Figure: 20-01-04un Title: Oxidation of cysteine Caption: Cysteine is readily oxidized by ozone to cysteic acid. Notes: Keywords: cysteine, oxidation, ozone, cysteic acid

Figure: 20-01-05un Title: Oxidation of methionine Caption: Methionine is oxidized by ozone to methionine sulfoxide. Notes: Keywords: methionine, oxidation, ozone, methionine sulfoxide

Figure: 20-01-06un Title: Oxidation of tryptophan Caption: Tryptophan is oxidized by ozone which undergoes a ring-opening at the double bond. Notes: Keywords: tryptophan, oxidation, ring-opening, double bond

Figure: 20-01-07un Title: Caption: Microorganisms in the digestive tract reduce nitrates to nitrites. Nitrite ions oxidize iron in hemoglobin to form methemoglobin which is incapable of carrying oxygen. Notes: Keywords: nitrate, nitrite, hemoglobin, methemoglobin, oxygen, reduce, oxidize

Figure: 20-01-08un Title: Antidote for cyanide poisoning Caption: Thiosulfate ions transfer sulfur atoms to the cyanide ions, converting them to the harmless thiocyanate ions. Notes: Keywords: antidote, cyanide, thiosulfate, sulfur, thiocyanate

Figure: 20-02 Title: Effect of copper ions on oat seedlings Caption: The effect of copper ions on the height of oat seedlings. From left to right, the concentrations of Cu2+ are 0, 3, 6, 10, 20, 100, 500, 2000, and 3000 μg/L. The plants on the left show varying degrees of deficiency; those on the right show copper ion toxicity. The optimum level of Cu2+ for oat seedlings is therefore about 100 μg/L. Notes: Keywords: copper ion, oat seedling, deficiency, height

Figure: 20-03 Title: Mercury poisoning Caption: Mercury poisoning. Enzymes catalyze reactions by binding a reactant molecule at the active site. Mercury ions react with sulfhydryl groups to change the shape of the enzyme and destroy the active site. Notes: Keywords: mercury, poisoning, enzyme, sulfhydryl, active site

Figure: 20-03-01L Title: British antilewisite (BAL) Caption: British antilewisite is an antidote for mercury poisoning. It works by chelating mercury ions, surrounding the ions so that they are tied up and unable to attack vital enzymes. Notes: Keywords: BAL, mercury, antidote, poisoning, chelating, enzyme, British antilewisite

Figure: 20-03-02un Title: EDTA-treatment for lead poisoning Caption: Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that can be used to treat lead poisoning. Notes: Keywords: lead, poisoning, EDTA, ethylenediaminetetraacetic acid, chelating

Figure: 20-03-03un Title: Lead-EDTA complex Caption: A lead-EDTA complex. Notes: Keywords: EDTA, lead, chelate

Figure: 20-03-07un Title: Hydrolysis of acetylcholine Caption: The neurotransmitter acetylcholine is hydrolyzed to choline and acetic acid by the enzyme acetylcholinesterase. Notes: Keywords: acetylcholine, acetylcholinesterase, enzyme, hydrolyze, choline, acetic acid

Figure: 20-04 Title: The acetylcholine cycle Caption: The acetylcholine cycle. Notes: Keywords: acetylcholine, presynaptic cell, postsynaptic cell, acetylase, cholinesterase

Figure: 20-04-01un Title: Atropine Caption: Atropine acts by blocking acetylcholine receptor sites. Notes: Keywords: atropine, acetylcholine, receptor

Figure: 20-05 Title: Acetylcholinesterase Caption: (a) Acetylcholinesterase catalyzes the hydrolysis of acetylcholine to acetic acid and choline. (b) An organophosphate ties up acetylcholinesterase, preventing it from breaking down acetylcholine. Notes: What functional group splits in the hydrolysis of acetylcholine? Keywords: acetylcholinesterase, hydrolysis, acetylcholine, organophosphate, acetic acid

Figure: 20-06 Title: Organophosphorous compounds Caption: Three organophosphorus compounds used as nerve poisons in chemical warfare. Compare these structures with those of the insecticides malathion and parathion. Notes: Keywords: organophosphorous, nerve poison, insecticide, malathion, parathion

Figure: 20-06-01un Title: Oxidation of nicotine Caption: Nicotine is oxidized to cotinine by the liver. Notes: Keywords: liver, cotinine, nicotine, oxidation

Figure: 20-06-02un Title: The liver as a detoxifier Caption: Toluene, which is insoluble in water, is oxidized by the enzyme P-450(found in the liver) into benzoic acid. The benzoic acid then couples with glycine to form hippuric acid, which is soluble in water and is readily excreted from the body. Notes: Keywords: toluene, soluble, insoluble, oxidized, P-450, enzyme, glycine, benzoic acid, hippuric acid, liver, detoxification

Figure: 20-06-03un Title: Oxidation of benzene Caption: Benzene is slowly oxidized in the liver to an epoxide. Notes: Keywords: benzene, oxidize, epoxide, liver

Figure: 20-07 Title: Cancer risks Caption: Ranking cancer risks. About 30% of all cancer deaths are attributed to tobacco and another 30% or so to a diet high in fat and calories and low in fruits and vegetables. Environmental pollution and food additives rank high in public perception of causes, but are only relatively minor contributors to cancer deaths. (Based on data from Harvard University School of Public Health.) Notes: Keywords: cancer risk, diet, tobacco, genetics, occupational, alcohol, pollution

Figure: 20-07-01un Title: Benzidine Caption: Benzidine is an aromatic amine that is a known carcinogen. Notes: Keywords: benzidine, carcinogen, aromatic amine

Figure: 20-08 Title: Heterocyclic carcinogens Caption: Three small-ring heterocyclic carcinogens. Notes: To what family of compounds does each compound belong? Keywords: heterocyclic, carcinogen, bis(epoxy)butane, beta propiolactone, N-laurylethyleneimine

Figure: 20-09 Title: The Ames test Caption: The Ames test. The top petri dish, to which a mutagenic chemical has been added, shows the growth of several colonies of Salmonella bacteria, indicating that mutations have occurred. The bottom dish is a control that shows only a few spontaneous mutations. Notes: Keywords: Ames test, petri dish, Salmonella bacteria, mutagenic

Figure: 20-09-01un Title: Thalidomide Caption: Thalidomide is a known teratogen. It caused birth defects characterized by shortened or absent arms and legs. Notes: Keywords: thalidomide, teratogen, birth defect

Figure: 20-09-03 Title: Isotretinoin Caption: Isotretinoin (accutane) is used for the treatment of acne. It can cuase multiple severe malformations when taken during pregnancy. Notes: Keywords: teratogen, accutane, isotretinoin, acne, pregnancy

Figure: 20-10 Title: A hazardous waste incinerator Caption: A schematic diagram of an incinerator for hazardous wastes. Question: PCBs are burned in air at high temperatures to carbon dioxide,water, and hydrogen chloride. Write the equation for the incineration of the PCB component C6H2Cl3—C6H3Cl2. Notes: Keywords: incinerator, hazardous waste

Figure: 20-T01 Title: LD50 values for some common substances Caption: LD50 values for some common substances. Notes: Keywords: LD50, ethyl alcohol, sodium chloride, aspirin, nicotine, caffeine, acetaminophen

Figure: 20-T02 Title: Estimated LD50 values for some more lethal poisons Caption: Estimated LD50 values for some more lethal poisons. Notes: Keywords: LD50, lethal, poison, sodium cyanide, arsenic, rotinone, strychnine, tetnus, botulin, muscarine

Figure: 20-T03 Title: Industrial products and hazardous waste by-products Caption: Industrial products and hazardous waste by-products. Notes: Keywords: industrial, hazardous waste, by-product, plastics, pesticides, medicines, paints, oils, metals, leather, textiles