Summer Research Program for Science Teachers/Partners in Science Program - 1997

Jacqueline Watt-Daniels


Beta-oxidation of unsaturated fatty acids


LABORATORY EXERCISE: Determination of Protein Concentration

Aim: How much protein is contained in an unknown sample? [9-12 Content Standard A- Identify questions, concepts that guide inquiry]

Materials needed:

10 test tubes

Standard protein stock solution


Bio-Rad dye

Unknown protein sample from E. coli [Teaching Standard D- Make accessible science tools]


1. Have students select the participants in their group

2. Limit each group to no more than 4 students

3. Obtain 10 test tubes and mark them as follows: 2 tubes (2 microliters), 2 tubes (4 microliters), 2 tubes (6 microliters), 2 tubes (8 microliters) and 2 tubes (10 microliters)

4. Add 1 milliliter of Bio-Rad (1:4) with water to all tubes and vortex

5. Add the above quantity of protein standard to each tube

6. Incubate tubes for 10 minutes each

7. Using the spectrophotometer take the absorbency of all tubes at 595 nm [Content Standard Unifying Concepts- Change, constancy, and measurement]

8. Plot points of absorbency versus the microgram of protein [9-12 Content Standard A- Use mathematics to improve communication]

9. Repeat for the unknown (two tubes)


Students will have to determine their information as part of a group


1. Students will have to present their information as part of a group [9-12 Content Standard A- Communicate and defend arguments]

2. Students will also graph the absorbency versus the micrograms of protein


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