Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 438 - Spring 2011


Week 13


Fatty Acid Oxidation

Calculate the P/O ratio for the aerobic catabolism of stearate (C=18). Show all work in a table such as we have used in class. KEY

 Exercise:Trace the synthesis of ketone bodies starting with glucose (assume that the organism goes from well fed to starving during this synthesis). Your discussion should include the most likely tissues involved.

  • How many acetoacetate molecules could be synthesized from four initial glucose molecules (assume all processes take place in a single cell).
    • Would glucose be used to make ketone bodies directly? Why or why not?
    • Is it more likely that fat is made first, then used to make acetoacetate later?
  • Determine the energy available from these acetoacetate molecules in ATP equivalents:
    1. Create a table as we have done in class, considering only the acetoacetate molecules themselves.
    2. Does the answer in (1) gives a good estimate of the energy actually used by the organism? As a check try making a table following the path for making and using the acetoacetates. As a simplification, include only the major carbon flux pathways in your table (e.g. glycolysis, beta-oxidation, fatty acid biosynthesis, etc.)
      1. Is this Table a reasonable approximation? Why or why not? (Look carefully.)


From the Final Exam Study Guide:

Fat Metabolism

beta-Oxidation of Fatty Acids:

Ketone Bodies




C438 Home

C438 Lecture Notes

©R A Paselk

Last modified 20 April 2011