DIGESTING LACTOSE WITH LACTASE Lab Conclusions

Background Information

Part A Directions Fill each clean test tube with 1 mL of the sample to be tested. Test tube 1: 1ml glucose solution Test tube 2: 1ml milk Test tube 3: 1ml lactase solution Test tube 4: 1ml milk plus 3 drops lactase solution (swirl gently to mix)

Part B Directions Perform a Glucose test on each test tube using Benedict ’s reagent Add 5-7 drops of Benedict’s Solution. Heat test tube in a hot water bath for 3-5 minutes. Check/Record color change. A positive result will be orange.

TABLE 1: RESULTS OF TEST FOR GLUCOSE Test tubeContentsBenedict’s Test ColorIs it positive (+) or negative (-) for glucose? BEFOREAFTER 1Glucose blue orange + 2Milkblue purple _ 3LactaseblueLight blue _ 4Lactase + Milk blue orange +

Conclusions Lactose in milk can be broken down into glucose and galactose. We tested to see if the lactose in milk was broken down by detecting glucose We used Benedicts’ reagent to detect glucose The milk tested positive for glucose with lactase added in test tube 4 but was negative for glucose with out the lactase in test tube 2 We can conclude that the added lactase caused lactose to be broken down because of the positive glucose test