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Ling Chen
Associate Professor of Chemistry
Science Department
Borough of Manhattan Community College / City University of New York
Cooking Under Pressure: Applying the Ideal Gas Law in the Kitchen

The Clarksons are making dinner for friends and decide to try out their new pressure cooker. As students read the dialogue that ensues, they learn about how the boiling point of water is directly related to external pressure, apply the ideal gas law, and relate chemical reaction rates with temperatures in addition to learning about the conservation of energy. Designed for a non-majors’ general chemistry course, the case could be extended to other disciplines, including physics, nutrition, and microbiology.

Dust to Dust: The Carbon Cycle

Tom and his grandfather, a retired high school chemistry teacher, are talking about a National Geographic television documentary titled “Waking the Baby Mammoth.” As students read the dialogue that ensues, they learn how carbon, an essential element of life, is transformed from carbon dioxide to carbohydrate to animals, then back to carbon dioxide. The case emphasizes a number of chemistry concepts, including atomic structures, carbon isotopes, radiocarbon dating, beta decay, half-life, and photosynthesis. Developed as a supplement to the nuclear chemistry chapter in a non-majors general chemistry course, the case could also be used in an introductory botany, paleobiology, plant, or general ecology course after students have completed at least one semester of general chemistry.

Fat Facts: Comparing the Structure and Function of Lipids

It's Mother's Day and Dolly, a high school senior, is making a Mediterranean salad for her mom, who is a college chemistry major and who likes to take every opportunity to teach Dolly what she has learned in school. Today is no exception, as she guides Dolly through a chemistry lesson in the kitchen. The case compares and contrasts the structures of various fatty acids, saturated with unsaturated, monounsaturated with polyunsaturated, and cis-conformation with trans-conformation. The melting point differences of saturated, monounsaturated, and polyunsaturated fatty acids also are explained as are the structures and functions of triacylglycerol, phospholipid, HDL cholesterol, LDL cholesterol, and omega-3 fatty acids. The case could be used in courses in general chemistry, organic chemistry, biochemistry, nutrition, biology, and food science.

Sweet Truth: Not All Carbohydrates Are Alike

This case reviews concepts of monosaccharide, disaccharide, and polysaccharide and contrasts the structures of different pairs of carbohydrates as well as the structure of sorbitol, a sugar substitute. It also depicts stereo chemistry concepts such as chiral carbon, enantiomer, anomer, Fisher projection, Haworth structure, and glycosidic bonds. In addition, the story associates the similar symptoms related to the gastrointestinal bacteria fermentation of lactose and soluble fibers and compares the enzymes that are responsible for the breakdown of lactose, amylose and cellulose. Furthermore, the case explains the health benefits of consuming insoluble fibers to prevent situations like constipation, diverticulosis, and colon cancer. Finally, the case study highlights the pros (for example, lowering absorptions of fats and glucose to prevent heart disease and the spike of the blood sugar levels after meals) and the cons (such as causing bloating and flatulence) of soluble-fiber consumption.

The Secret of Popcorn Popping: Water Power at the Cellular Level

Focusing on the important role of water in living cellular chemistry, this case emphasizes the general solubility rule, "like dissolves like," which explains how water can serve as a medium for transporting the cell's soluble nutrients and wastes. The case covers how the different interactions between water and glycerophospholipids' polar heads and non-polar tails direct the formation of the cell's membrane bilayer, and teaches students that water is instrumental in positioning amino acids according to their polarities during protein folding. Also reviewed are the chemical reactions of water during photosynthesis, respiration, dehydration, and hydrolysis. The case has been used with nursing students in the second semester of a General, Biological, and Organic Chemistry course. It can also be used as a review of basic biology and chemistry for upper level students in biochemistry.