lab identifying macromolecules in food july 31 2012 1 
Teacher’s Guide
EXPLORE
Part I: Testing Known Substances
Teacher Prep:
1. Prepare and label four Erlenmeyer flasks and disposable pipettes with the following suggested solutions and place them in the front of the room for easy access for students:
a. Polysaccharide Solution - blended potato or lab grade starch solution
b. Monosaccharide Solution – apple juice or lab grade glucose solution
c. Protein Solution – blended meat or egg whites
d. Lipid Solution – vegetable oil, melted butter
2. Set up 4 lab stations (twice around the room) for students to rotate. Each station should have the materials needed to conduct one of the following tests:
a. Iodine Test: starch + iodine (yellowish orange) blue-black
Ex. Potato solution
b. Benedict's Test: monosaccharide + Benedict's solution (light blue) green to red depending on concentration of sugars
Ex. apple juice or glucose solution
c. Biuret's Test: protein solution + Biuret’s solution (light blue) pinkish purple Ex. meat , egg white
d. Paper Bag (Translucence) test
3. At each station, have the indicator test procedure card, the biomolecule information card for the biomolecule being tested at the station, and all lab supplies required to conduct the test. It is recommended that the two lab stations in the front be designated for the Benedicts test which requires a hot water bath.
Procedure
4. Have students read the background information and complete the Pre-Lab questions for Part 1 as the journal activity for the day.
5. Demonstrate to students what equipment and basic procedures they will be applying during this exercise.
6. Have students get into groups of 2-3 and rotate through all 4 stations and record their results.
7. Have students return to their desks but stay with their groups to complete the Analysis Questions in their journals.
Alternate indicators:
Iodine for lipids/oil (turns pink but transformation is temporary so watch carefully)
Biuret Solution is easy to make. Start with 40% NaOH and
EXPLORE
Part I: Testing Known Substances
Teacher Prep:
1. Prepare and label four Erlenmeyer flasks and disposable pipettes with the following suggested solutions and place them in the front of the room for easy access for students:
a. Polysaccharide Solution - blended potato or lab grade starch solution
b. Monosaccharide Solution – apple juice or lab grade glucose solution
c. Protein Solution – blended meat or egg whites
d. Lipid Solution – vegetable oil, melted butter
2. Set up 4 lab stations (twice around the room) for students to rotate. Each station should have the materials needed to conduct one of the following tests:
a. Iodine Test: starch + iodine (yellowish orange) blue-black
Ex. Potato solution
b. Benedict's Test: monosaccharide + Benedict's solution (light blue) green to red depending on concentration of sugars
Ex. apple juice or glucose solution
c. Biuret's Test: protein solution + Biuret’s solution (light blue) pinkish purple Ex. meat , egg white
d. Paper Bag (Translucence) test
3. At each station, have the indicator test procedure card, the biomolecule information card for the biomolecule being tested at the station, and all lab supplies required to conduct the test. It is recommended that the two lab stations in the front be designated for the Benedicts test which requires a hot water bath.
Procedure
4. Have students read the background information and complete the Pre-Lab questions for Part 1 as the journal activity for the day.
5. Demonstrate to students what equipment and basic procedures they will be applying during this exercise.
6. Have students get into groups of 2-3 and rotate through all 4 stations and record their results.
7. Have students return to their desks but stay with their groups to complete the Analysis Questions in their journals.
Alternate indicators:
Iodine for lipids/oil (turns pink but transformation is temporary so watch carefully)
Biuret Solution is easy to make. Start with 40% NaOH and