Gluconeogenesis is the production of glucose from which sources?

Gluconeogenesis is the production of glucose from which sources?

• A. Protein or fat
• B. Glucose
• C. Carbohydrates
• D. Glycogen

Answer: (A)

Gluconeogenesis builds glucose from non-carbohydrate precursors. The main sources are substrates derived from protein and fat: amino acids from protein can be converted into intermediates that enter the gluconeogenic pathway, and glycerol from fat can be converted into glycerol-3-phosphate and then into intermediates that feed gluconeogenesis. This process helps maintain blood glucose during fasting or when carbohydrate intake is low. Carbohydrates themselves are already glucose or can be broken down to glucose via glycolysis and glycogen breakdown (glycogenolysis), so they’re not substrates for gluconeogenesis. Therefore, using amino acids from protein or glycerol from fat aligns with gluconeogenesis, whereas using glucose or glycogen would involve other pathways.

Gluconeogenesis builds glucose from non-carbohydrate precursors. The main sources are substrates derived from protein and fat: amino acids from protein can be converted into intermediates that enter the gluconeogenic pathway, and glycerol from fat can be converted into glycerol-3-phosphate and then into intermediates that feed gluconeogenesis. This process helps maintain blood glucose during fasting or when carbohydrate intake is low.

Carbohydrates themselves are already glucose or can be broken down to glucose via glycolysis and glycogen breakdown (glycogenolysis), so they’re not substrates for gluconeogenesis. Therefore, using amino acids from protein or glycerol from fat aligns with gluconeogenesis, whereas using glucose or glycogen would involve other pathways.