MCAT Basics (from MedSchoolCoach) Gluconeogenesis
Aug 21, 2025
Joining as a guest host, Alex Starks, a physician, delves into the fascinating world of gluconeogenesis. He breaks down how the body ingeniously produces glucose from precursors like amino acids, lactate, and glycerol when supplies run low. Alex highlights the liver's crucial role and explains why muscle cells aren't involved in this process. He also touches on the energy demands and hormonal regulation by glucagon, making complex metabolic pathways understandable for MCAT prep.
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Gluconeogenesis Is Liver-Driven Glucose Production
- Gluconeogenesis means making new glucose from non-carbohydrate precursors when blood glucose is low.
- The liver (and kidneys slightly) perform this to maintain blood glucose for other organs like the brain.
Glycerol Can Make Glucose, Fatty Acids Cannot
- Glycerol from triglycerides enters gluconeogenesis as G3P after phosphorylation.
- Fatty acids themselves yield acetyl-CoA, which cannot be converted back into glucose.
Pyruvate Carboxylation Occurs In Mitochondria
- The first bypass converts pyruvate to oxaloacetate in mitochondria via pyruvate carboxylase and uses ATP.
- Bicarbonate is often shown instead of CO2 but functionally represents the same addition.