Procedure 7.5.b Determination of Cd2 Uptake by Atomic Absorption

Prepare a standard stock solution (1000 (xg/ml of Cd) by dissolving 1 g Cd metal (record exact mass) in a minimum volume of 1 1 HCl ddH20. Dilute to 1000 ml with ddH20. 

Using the optimum concentration range for Cd (0.05-2 mgl-1) prepare a series of six concentrations to be used in constructing a calibration curve for Cd. Record your concentrations and absorbance readings in the table in the Results Summary section. Plot the calibration curve for cadmium (absorbance vs concentration). 

Analyze the supernatant from your peptide isolation procedure using atomic absorption spectroscopy. Follow the directions for your particular instrument. Assuming 100% extraction, determine the amount of Cd taken up by the yeast. Make dilutions of your supernatant as needed using ddH20. 

Results Summary for the Biosynthesis of PC and Cd2+ Binding in a Yeast Model 

Read up on the biochemistry of Cd2+ as a heavy metal. Why might yeast and plants biosynthesize phytochelatins to sequester this ion What happens to this when it enters the cell What would happen if it were released from storage  

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