Fed state vs. fasting state metabolism — Flashcards

Flashcard 1: Glycerol, from triglyceride breakdown, travels to the liver and is converted to glucose via the process of _____

Answer: gluconeogenesis

Flashcard 2: Ketogenesis occurs in prolonged starvation and ketoacidosis due to the depletion of ________, which is used for gluconeogenesis and thus unavailable for the TCA cycle.

Answer: Oxaloacetate

Extra: In starvation and diabetic ketoacidosis (DKA), oxaloacetate (OAA) is consumed for gluconeogenesis. This depletion of OAA prevents Acetyl-CoA from entering the TCA cycle, shunting it instead into the production of ketone bodies.

Flashcard 3: Pyruvate carboxylase is regulated via positive feedback by _____

Answer: acetyl-CoA

Flashcard 4: What is the major source of energy while fasting between meals? _____

Answer: Hepatic glycogenolysis

Flashcard 5: What is the major source of energy during fasting (1-3 days)? _____

Answer: Hepatic gluconeogenesis

Flashcard 6: During oxidative phosphorylation, how many ATP are produced per FADH2?

Answer: 1.5 (Classic value: 2)

Extra: According to modern P/O ratios: - NADH produces ~2.5 ATP - FADH2 produces ~1.5 ATP Older textbooks often use the rounded integers 3 and 2 respectively.

Flashcard 7: Where does oxidative phosphorylation take place?

Answer: mitochondria

Flashcard 8: Where does the TCA cycle take place?

Answer: mitochondria

Flashcard 9: Where does acetyl-CoA production take place?

Answer: mitochondria

Flashcard 10: Where does heme synthesis occur?

Answer: steps in both the cytoplasm and mitochondria