Glycolysis

• Aerobic and anaerobic glycolysis can be described
• Importance, fate of products, and important intermediates of aerobic and anaerobic glycolysis can be explained
• Regulation of glycolysis can be explained
• Glucose is generated through gluconeogenesis and is engaged in the synthesis of lipids and amino acids
• Glycolysis degrades glucose to pyruvate, generating 7 ATP (lactate under anaerobic conditions)
• Citric acid cycle oxidizes acetyl CoA to CO2
• Gluconeogenesis synthesizes glucose from non-carbohydrate precursors
• Glycogenesis synthesizes glycogen from glucose
• Glycogenolysis breaks down glycogen to glucose, then to lactate or pyruvate
• Hexose monophosphate shunt is an alternative pathway to glycolysis and TCA cycle for glucose oxidation
• Carbohydrates are the main energy source for the body
• Glucose is the preferred energy source for most body tissues
• Brain cells mainly derive energy from glucose
• Pyruvate is the end product of aerobic glycolysis
• Lactate is the end product of anaerobic glycolysis
• Glycolysis occurs in all cells of the body
• Anaerobic glycolysis is a major energy source for muscle during exercise
• Glycolysis provides carbon skeletons for the synthesis of non-essential amino acids
• Insulin controls the entry of glucose from extracellular fluid to intracellular fluid
• Glycolysis is a prerequisite for the aerobic oxidation of carbohydrates
• Aerobic oxidation occurs in cells with mitochondria
• Glycolysis is the major pathway for ATP synthesis in tissues lacking mitochondria (e.g., erythrocytes)
• Steps of glycolysis:
• Steps 5 and 10 of glycolysis are coupled
• Glycolysis is the major source of energy in anaerobic conditions
• Formation of lactate allows the regeneration of NAD+
• Fate of pyruvate depends on the presence of oxygen in cells
• Glycolysis is crucial in skeletal muscle during strenuous exercise
• Brain, retina, renal medulla, and GI tract derive energy from glycolysis
• Energetics of glycolysis:
• Shuttle pathways can produce 2 or 3 ATP depending on the cytosolic NADH shuttle used
• Regulation of glycolysis by insulin, glucagon, and glucose-6-P
• Regulation by PFK-2 in response to blood glucose levels
• Pasteur effect inhibits glycolysis by oxygen
• Rapoport Luebering shunt bypasses the kinase reaction in erythrocytes
• Fate of pyruvate under aerobic conditions involves transport into mitochondria via pyruvate transporter and conversion to Acetyl CoA
• Lactic acidosis can be caused by various factors affecting pyruvate metabolism