Glucose Catabolism
Glucose Catabolism - Related Videos
01:30
Carbohydrate Catabolism
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2025
Carbohydrate catabolism is a fundamental process in cellular metabolism that enables energy extraction from glucose through two primary pathways: cellular respiration and fermentation. Both pathways begin with glycolysis, which operates independently of oxygen availability.Glycolysis: A Shared Starting PointGlycolysis is an oxygen-independent process that breaks down glucose into two molecules of pyruvic acid. During this process, a net gain of two ATP molecules and two NADH molecules is...
01:25
Lipid Catabolism
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2025
Triglycerides serve as crucial long-term energy storage molecules in microorganisms, providing a dense source of metabolic energy. Their breakdown is mediated by lipases, which hydrolyze triglycerides into glycerol and free fatty acids. Each of these components follows distinct metabolic pathways, ultimately contributing to ATP synthesis and cellular energy homeostasis.Glycerol MetabolismGlycerol, released from triglyceride hydrolysis, is phosphorylated by glycerol kinase to form...
01:18
Amino Acid Catabolism
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2025
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...
05:52
In Vitro Glucose Depletion Assay: A Fluorescence-Based Method to Quantify Cellular Glucose Uptake via Extracellular Glucose Depletion Measurement
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2025
This video demonstrates an in vitro assay to indirectly measure intracellular glucose uptake. The assay uses a fluorescently-labeled glucose analog to establish a correlation between extracellular glucose depletion and intracellular glucose uptake.
02:23
Oral Glucose Tolerance Test (OGTT): Measuring Glucose Metabolism in Mice
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2023
This video introduces how to perform an oral glucose tolerance test on a laboratory mouse.
FAQs
ATP serves as directly usable cellular energy, whereas NADH carries high-energy electrons generated during glycolysis and subsequent oxidative steps. When oxygen is available, those electrons support oxidative phosphorylation, which produces additional ATP. This distinction explains why glucose breakdown supplies both immediate energy and reducing power for later energy production.
After glycolysis produces pyruvate, sufficient oxygen permits conversion to acetyl-CoA, oxidation in the citric acid cycle, and electron use in oxidative phosphorylation. When oxygen is insufficient, fermentation replaces these downstream steps and produces a lower energy yield. Thus, oxygen availability changes both the route taken and the amount of usable energy obtained.
Fermentation regenerates NAD+, allowing glycolysis to continue when oxygen is insufficient. This matters because glycolysis depends on the continued availability of NAD+ while converting glucose into pyruvate. Although fermentation does not provide the greater energy yield associated with oxidative phosphorylation, it preserves glycolytic energy production under oxygen-limited conditions.
Begin with glycolysis in the cytosol, where one glucose becomes two pyruvate while ATP and NADH are generated. If oxygen is available, trace pyruvate conversion to acetyl-CoA, followed by the citric acid cycle and oxidative phosphorylation. Under insufficient oxygen, instead follow fermentation after glycolysis and account for its lower energy yield.
The pathways produce ATP for usable cellular energy, NADH for electron transfer, and pyruvate as a central product of glycolysis. With oxygen, pyruvate contributes to acetyl-CoA formation and further oxidation. The process also supplies metabolic intermediates, so glucose breakdown supports both energy demands and the cellular materials needed for growth.
Glucose catabolism provides a framework for examining how cells meet energy demands during growth and exercise. Its pathway structure also makes it relevant to research on diabetes and mitochondrial dysfunction, where altered energy-related processes may be important. Comparing glycolytic, fermentative, and oxygen-dependent stages helps researchers relate cellular metabolism to broader biological conditions.