Questions to ponder? How can we determine if a substance is carb, protein, or lipid?

Questions to ponder? How can we chemically determine if a substance is carb, protein, or lipid? What about different kinds of carbs? (simple vs. complex?)

Test for simple sugars Benedict’s reagent will turn from blue to green, yellow or red with increasing levels of sugar concentrations after heat is applied

Test for complex sugars (aka starch) Iodine reagent will turn from a light yellow to a dark blue or black in the presence of starch

Test for proteins Biuret reagent will turn from blue to pink or purple in the presence of peptide bonds

Test for lipids?

Materials list Known substances: Potato juice Glucose Pepsin/albumin Canola oil Whole potato Whole onion Water Reagents: Benedict’s Biuret Iodine Plenty of test tubes and test tube racks Lots of water Markers/pens Brown paper bags Set of unknown substances A – half and half B – diluted red wine C – ginger ale D – Grandma’s® PB cookie E – Ritz chips – sour cream/onion F – turkey with broth baby food G – ham from Schnucks deli

Hints: For each reagent, test a known positive and a known negative, so that you will have a basis for comparing your unknown results. Keep these until you are completely finished! Be sure to keep your measurements standard across tests of a single reagent. Keep test tubes less than half full – no explosions! Dilute each test with about equal volumes of water to clearly see any color change

Questions to Test: Does amylase (an enzyme) eat up starch? Will an emulsifier make oil mix with water?