Exercise 8.2 - Chlorophyll Content
- Chloroplast suspension from Exercise 8.1
- Spectrophotometer and tubes
- Clinical centrifuge and tubes
- Pipet 1.0 ml of a chloroplast suspension into a 15 ml
centrifuge tube and add 8.0 ml of acetone. Mix thoroughly.
- Add 1.0 ml of distilled water, mix again and centrifuge at
1000 xg for 3-5 minutes.
- Turn on a spectrophotometer, adjust the wavelength to 652 nm
and blank the instrument with water.
- Measure the absorbance of the supernatant from step 2.
- Calculate the amount of total chlorophyll in 1.0 ml of the
chloroplast suspension. 2 The amount of chlorophyll is givenby the equation:
- Calculate the dilution factor for your original chloroplast
suspension so that when diluted with suspension solution, the
final concentration of chlorophyll will be 0.01 mg/ml.
All subsequent work with chloroplasts will use the diluted
suspension so that the criterion of step 6 is met.
- Use a hemacytometer to determine the number of chloroplasts
per ml of any diluted suspensions.
Absorbance of acetone extracted chlorophyll solution = ___________
Calculated concentration of chlorophyll = ____________mg chlor./ml
Dilution factor for suspension to yield 0.01 mg chlorophyll/ml = ___________
Chloroplasts/ml of suspension so diluted = ___________
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Cell Biology Laboratory Manual
Dr. William H. Heidcamp, Biology Department, Gustavus Adolphus College,
St. Peter, MN 56082 -- email@example.com