Which two cell types require a constant supply of glucose?

Which two cell types require a constant supply of glucose?

• A. Muscle fibers and neurons
• B. Brain and red blood cells
• C. Liver and adipose tissue
• D. Pancreatic islets

Answer: (B)

Glucose must be available continuously for cells that either cannot use other fuels or rely entirely on glycolysis for energy. Red blood cells have no mitochondria, so their ATP production comes solely from glycolysis and they depend on a steady glucose supply to function. The brain has a very high and constant energy demand and, in normal conditions, relies on glucose to support neuronal activity and maintain ion gradients, though it can adapt somewhat during prolonged fasting; without a continued glucose supply, brain function quickly falters. Other tissues can use fatty acids or ketone bodies for energy, so they don’t require glucose at the same constant rate.

Glucose must be available continuously for cells that either cannot use other fuels or rely entirely on glycolysis for energy. Red blood cells have no mitochondria, so their ATP production comes solely from glycolysis and they depend on a steady glucose supply to function. The brain has a very high and constant energy demand and, in normal conditions, relies on glucose to support neuronal activity and maintain ion gradients, though it can adapt somewhat during prolonged fasting; without a continued glucose supply, brain function quickly falters. Other tissues can use fatty acids or ketone bodies for energy, so they don’t require glucose at the same constant rate.