Chapter 16 Flashcards
(3 cards)
Where does glycolysis and CAC occur?
Glycolysis occurs in the cytoplasm
Citric acid cycle occurs in the mitochondrial matrix†
Oxidative phosphorylation occurs in the inner membrane
How are E1, E2, and E3 of the PDH complex regulated? Why is it so important that this step is regulated?
High levels of ATP inhibit E1 of PDH
High levels of Acetyl CoA inhibit E2 of PDH
High levels of NADH inhibit E3 of PDH
Formation of CoA is irreversible, so this is a major control step!! High levels of products
from the Citric Acid Cycle prevent Acetyl CoA from being formed so that it cannot enter the Citric Acid Cycle when ATP is not needed.
Regulation of the Citric Acid Cycle: Integration with other pathways
When isocitrate dehydrogenase is inhibited, citrate levels rise:
Isocitrate readily converted back to citrate
Citrate can signal PFK to stop glycolysis
Citrate can be used as source of acetyl CoA for fatty acid synthesis
When a-ketoglutarate dehydrogenase is inhibited, a-ketoglutarate levels rise:
Used as precursor for amino acids
Used as precursor for purine bases
