Intermediary metabolism

norcalguy
Mon, 02 Feb 2009 18:30:32 +0000

And simply memorizing the structures of the intermediates isn’t useful. Many of our questions were more conceptual. For example, what happens when your blood sugar is low? You’ll stimulate glycogen breakdown in the muscle and liver, take up free fatty acids and ketoacids in the muscle, start fatty acid oxidation, make glucose de novo and export it from the liver, make ketone bodies in the liver, hydrolyze fatty acids in fat cells. Obviously, in this one question alone, you have to know something about glycogen breakdown, fatty acid oxidation, gluconeognesis, ketone bodies synthesis, and lipase-mediated hydrolysis of fatty acids. But, do you need to know the 5th intermediate in the synthesis of a ketone body? No. Should you know what ketone bodies are synthesized from (acetyl CoA from fatty acid oxidation), where they’re synthesized (liver), where they’re used (heart/brain), when they’re released (fasting state), and the basic structure? Yes.

That’s why it’s so important to know how each of these pathways are interrelated and which pathways are inhibited and which pathways are stimulated in which situations.