Intro to Glucose Metabolism 

  • GlucosemetabolismGlucose metabolism:
    • a process where our bodies try to transform the energy stored in the bonds of sugar molecules (glucose) instead of ATP
  • Glucose is metabolized inside the cytoplasm into two pyruvate molecules and a net result of two ATP molecules.
    • this is called glycolysisglycolysis
  • Glycolysis doesn’t require oxygen to take place making it an anaerobicprocessanaerobic process. Under anaerobic conditions, the pyruvate molecules can be transformed into either lactate or ethanol via ==fermentation==.
  • Under aerobic conditions, pyruvate molecules will move into the mitochondria
    • in the mitochondria, there are other processes like pyruvate decarboxylation and citric acid cycle
  • In the presence of oxygen, certain organisms can ultimately use the O2 to transform pyruvate molecules into CO2 and ATP molecules. T
  • AerobicCellularRespirationAerobic Cellular Respiration:
    • the utilization of O2 to transform glycolysis by-products into high energy molecules
    • includes processes that take place in the mitochondria but also glycolysis itself.
  • When cells have high levels of ATP, pyruvate and lactase molecules can be recycled to reform the glucose via ==gluconeogenesis==. Glycolysis and gluconeogenesis don’t occur in the cell at the same time; when one is activated, the other is inhibited.
  • How do these glucose molecules make their way into the cells of our bodies?
    • via the ingestion of food
    • meals rich in carbs
    • polysaccharides from plants (starches)
      • amylose and amylopectin
    • polysaccharides from animals (glycogen)
  • These polysaccharides are too large for blood transport and cell uptake. Therefore, our digestive system utilizes proteases to break them down.
  • What are the enzymes that break down carbs into their individual monomeric form?
    • Salivary alpha-amylose
    • begins to cleave alpha 1,4-glycosidic linkages in the mouth. This breaks down into polysaccharides and oligosaccharides
    • Pancreatic alpha-amylose
    • the pancreas releases a more potent alpha-amylose into the small intestine that breaks it down into disaccharides (maltose) and trisaccharides (maltotriose)
    • Maltase (brush border)
    • an enzyme that breaks down maltose into its glucose constituents
    • Alpha-glucosidase
    • digest maltotriose and other glucose-based oligosaccharides
    • Alpha-dextrinase
    • breaks down limit dextrin units that are alpha 1,6-linkages
    • Sucrase and lactase (brush border)