AICE Biology Lab Review - SchoolWorld an Edline Solution：丽斯生物学实验室审查schoolworld一艾里尼溶液.ppt

AICE Biology Lab Review: Biological Molecules Enzymes B. Biological Molecules (a) carry out tests for reducing and non-reducing sugars (including semi-quantitative use of the Benedict’s test), the iodine in potassium iodide solution test for starch, the emulsion test for lipids and the biuret test for proteins; Benedict’s Test: Reducing Non Reducing Sugars, Round 1 RESULTS: Aqua-blue = negative. Green to Yellow to orange = positive. Note: to detect the simple sugar sucrose, you must do round 2 test Left to right: Benedicts reagent (BnR), potato extract + BnR, onion extract + BnR, 5% glucose + BnR. Testing for simple sugars: Benedicts Reagent, round 1 Procedure: Add Benedicts reagent to sample, place in waterbath until just boiling. Benedict’s Test: Reducing Non Reducing Sugars, Round 2 A Negative result in round one DOES NOT mean an absence of carbohydrates!! Sucrose is a non-reducing Sugar can only be detected by doing round 2 of Benedict’s testing (Acid Hydrolysis) Procedure: Perform round 1 of Benedict’s Testing. Negative result indicates either no carbohydrate OR Non-reducing Sugars (Sucrose or starch). How would you test for the presence of starch??? Perform Round 2 of Benedict’s Testing to see if you have sucrose if Starch test is Negative. Sample Procedure for Benedict’s Test for Non Reducing Sugar In a test tube place 5 cm3 solution, add 3 cm3 Benedicts reagent to the solution in the test tube and place the tube in the boiling water bath for five minutes. Add 1 cm3 dilute hydrochloric acid to the solution solution in your test tube. Note the time and place in the water bath After 10+ minutes, remove the tube from the water bath cool it under the tap. Neutralize the acid by adding solid sodium bicarbonate, a little at a time, until the addition of one portion produces no fizzing. With a dropping pipette place 3 cm3 Benedicts solution in test tube return to the water bath and heat for five minutes. A color change indicates that the