macromolecules labpack[1]
Post on 26-Jun-2015
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Teacher’s Notes:
I use the following materials to make the unknown solutions:
Corn starch, albumin or egg white, glucose/dextrose To create a 1% solution, add 1g of your substance to 100 mL of
water. You can heat the water slightly to help dissolve the solids, if need be, but do not bring to a boil (especially the egg white)! Test your stock solutions to make sure you are able to observe a positive color change. If not, you may need to up the concentration of the solution.
All solutions except egg white will keep just fine in the fridge, but I would remind students to stir them before use in case the solute settles out of the solution.
Suggested solutions & expected results:A. Glucose (+ Benedicts reagent, blue to rusty orange or “puke” green)B. Corn starch (+ Iodine solution, amber to inky black)C. Albumin and glucose (+ Biuret reagent, blue to violet and + Benedicts
reagent, blue to rusty orange or “puke” green)D. Albumin (+Biurets reagent, blue to violet)E. “Control” distilled or tap water (- all reagents)
In the shortened version on the lab, just have three solutions and “D” would be the control/water.
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