Fall SAVY 2016 (Day 5) – Intro to Macromolecules
This week in Intro to Macromolecules, we began by reviewing our lipid lab results from last week. The acetone in which we had extracted the lipids had evaporated and what remained was the fat isolated from each type of food. The students observed that the lipid layer isolated from chocolate chips was relatively solid, while the lipids extracted from the potato chips and sunflower seeds were liquid. Based on these results and our discussion from the previous week, the students concluded that chocolate chips contain primarily saturated fat whereas potato chips and sunflower seeds contain primarily unsaturated fats; we were even able to verify our conclusions by consulting the nutrition facts label from each food! We wrapped up our discussion of lipids by breaking into groups to read about three different areas of further interest: anabolic steroids, trans fats, and phospholipid bilayers. Ask your student to give you the presentation that he/she gave the class on his/her group’s topic.
Next we studied our final class of macromolecule—proteins. Proteins are classified as macromolecules because they consist of repeating amino acid monomers. The students were intrigued by the fact that different combinations of only 20 amino acids can result in the thousands of diverse proteins in living things. We spoke briefly about how the order of the amino acids affects protein folding and overall structure, which ultimately determines protein function. We learned that proteins have many functions in the body, including playing structural role, serving as enzymes that catalyze reactions, transporting small molecules, helping with immunity, and, like the other macromolecules, providing us with energy. To conclude our morning, we had fun determining the effects of temperature on enzyme activity. Catalase is an enzyme that converts hydrogen peroxide to water and oxygen gas. Potatoes, among other foods, possess the catalase enzyme, so we ground up potatoes in a food processor and placed some of the “potato mush” at room temperature, some on ice, and some we microwaved for two minutes. We then added hydrogen peroxide to each and visually monitored the reaction. Talk with your student about his/her observations. How could he/she tell if a reaction had occurred? Did certain reactions proceed faster than others? Did any not work at all and, if so, why? (Feel free to repeat this experiment at home—you probably have the necessary reagents in your food pantry and medicine cabinet!)
Next week we will conclude our discussion of proteins and work to summarize and synthesize the information we have learned over the course of six weeks. We will also have the opportunity to hear from three scientists who are conducting research on each of the three classes of macromolecules. Finally, please join us next week at the conclusion of our class session (from 11:15-11:45 AM) for an open house. I have enjoyed working with your children and look forward to meeting you then.