glycolysis
(noun)
The breakdown of glucose (or other carbohydrates) by enzymes, generating ATP and pyruvate.
Examples of glycolysis in the following topics:
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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.
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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.
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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.
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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).
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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.
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Aerobic Training vs. Strength Training
- Aerobic activity relies on the availability of oxygen for energy production, whereas anaerobic activity utilizes primarily glycolysis.
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Muscle Fatigue
- In aerobic respiration, pyruvate produced by glycolysis is converted into additional ATP molecules in the mitochondria via the Krebs Cycle.
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Acidosis
- It is due to the accumulation of ketoacids (ketosis) and reflects a severe shift from glycolysis to lipolysis for energy needs.