glycolysis

(noun)

The breakdown of glucose (or other carbohydrates) by enzymes, generating ATP and pyruvate.

Related Terms

Examples of glycolysis in the following topics:

  • Muscle Metabolism

    • Glycolysis is the metabolic reaction which produces two molecules of ATP through the conversion of glucose into pyruvate, water, and NADH in the absence of oxygen.
    • The glucose for glycolysis can be provided by the blood supply, but is more often converted from glycogen in the muscle fibers.
    • Glycolysis alone can provide energy to the muscle for approximately 30 seconds, although this interval can be increased with muscle conditioning.
    • While the pyruvate generated through glycolysis can accumulate to form lactic acid, it can also be used to generate further molecules of ATP.

  • Internal Respiration

    • Glycolysis: The breakdown of glucose into pyruvate, ATP, H2O, and heat.
    • A diagram of cellular respiration including glycolysis, the Krebs cycle (also called the citric acid cycle), and the electron transport chain.

  • Slow-Twitch and Fast-Twitch Muscle Fibers

    • The ATP required for slow-twitch fiber contraction is generated through aerobic respiration (glycolysis and Krebs cycle), whereby 30 molecules of ATP are produced from each glucose molecule in the presence of oxygen.
    • Unlike slow-twitch fibers, fast twitch-fibers rely on anaerobic respiration (glycolysis alone) to produce two molecules of ATP per molecule of glucose.

  • Metabolic Changes

    • These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acid synthesis (6).

  • Insulin Secretion and Regulation of Glucagon

    • Glucagon also turns off glycolysis in the liver, causing glycolytic intermediates to be shuttled to gluconeogenesis that can induce lipolysis to produce glucose from fat.

  • Aerobic Training vs. Strength Training

    • Aerobic activity relies on the availability of oxygen for energy production, whereas anaerobic activity utilizes primarily glycolysis.

  • Muscle Fatigue

    • In aerobic respiration, pyruvate produced by glycolysis is converted into additional ATP molecules in the mitochondria via the Krebs Cycle.

  • Acidosis

    • It is due to the accumulation of ketoacids (ketosis) and reflects a severe shift from glycolysis to lipolysis for energy needs.