Name: glucose breakdown and atp production
Uploaded: 2025-06-12T09:33:28.000Z
Duration: 1 min 30 s
Channel: JoVE

Carbohydrate catabolism provides energy for cells through cellular respiration and fermentation.Both processes start with glycolysis and diverge into different pathways depending on oxygen availability.Glycolysis, an oxygen-independent process, oxidizes glucose into pyruvic acid, producing ATP and NADH.In cellular respiration, pyruvic acid enters the Krebs cycle, oxidizing to carbon dioxide and generating ATP, NADH, and FADH2.Electrons from NADH and FADH2 move along the electron transport chain, generating a proton gradient for ATP synthesis via oxidative phosphorylation.Oxygen is the final electron acceptor in aerobic respiration. Meanwhile, in anaerobic respiration in prokaryotes, the final electron acceptors are inorganic molecules like nitrates or sulfates.Fermentation occurs when oxygen is unavailable. It converts pyruvic acid into organic end products like lactic acid or ethanol.Fermentation relies solely on glycolysis to produce only 2 ATP per glucose molecule, while aerobic respiration produces 36 to 38 ATP from the complete oxidation of one glucose molecule.

koolhydraatkatabolisme

Carbohydrate Catabolism

Koolhydraatkatabolisme is een fundamenteel proces in de cellulaire stofwisseling waarbij energie uit glucose wordt onttrokken via twee primaire routes: cellulaire ademhaling en fermentatie. Beide routes beginnen met glycolyse, die onafhankelijk van de beschikbaarheid van zuurstof functioneert.
Glycolyse: Een Gedeeld Startpunt
Glycolyse is een zuurstofonafhankelijk proces dat glucose afbreekt tot twee moleculen pyruvaat. Tijdens dit proces wordt per glucosemolecuul een nettowinst van twee ATP-moleculen en twee NADH-moleculen behaald. Glycolyse fungeert als voorbereidende fase voor verdere energieonttrekking en stuurt de metabole stroom richting ademhaling of fermentatie, afhankelijk van de beschikbaarheid van zuurstof.
Cellulaire Ademhaling: Maximalisatie van de Energieopbrengst
In aanwezigheid van zuurstof wordt pyruvaat in de mitochondri&#235;n volledig geoxideerd via de citroenzuurcyclus en de elektronentransportketen (ETC). De citroenzuurcyclus produceert koolstofdioxide en genereert aanvullende energiedragers, waaronder NADH en FADH_2. Deze dragers transporteren elektronen naar de ETC, waarbij de energie van elektronentransport wordt gebruikt om protonen over het mitochondriale membraan te pompen, waardoor een protonengradi&#235;nt ontstaat. De terugstroom van protonen via ATP-synthase drijft de synthese van ATP aan, een proces dat oxidatieve fosforylatie wordt genoemd. Aerobe ademhaling gebruikt zuurstof als de uiteindelijke elektronacceptor, wat de productie van 36 tot 38 ATP-moleculen per glucosemolecuul mogelijk maakt. Anaerobe ademhaling daarentegen maakt gebruik van andere moleculen, zoals nitraat of sulfaat, als uiteindelijke elektronacceptoren, hoewel dit minder effici&#235;nt is dan aerobe ademhaling.
Fermentatie: Energieproductie bij Afwezigheid van Zuurstof
Wanneer zuurstof afwezig is, grijpen cellen terug op fermentatie om NAD^+ te regenereren voor de voortzetting van de glycolyse. Tijdens fermentatie wordt pyruvaat omgezet in organische producten, zoals melkzuur bij dieren of ethanol en koolstofdioxide bij gist. In tegenstelling tot cellulaire ademhaling levert fermentatie slechts 2 ATP-moleculen per glucosemolecuul op, aangezien het uitsluitend afhankelijk is van glycolyse voor energieproductie.
De keuze tussen deze metabole routes stelt organismen in staat zich aan te passen aan wisselende omgevingsomstandigheden, waarbij energie-effici&#235;ntie wordt afgewogen tegen de beschikbaarheid van hulpbronnen.

Koolhydraatkatabolisme

Koolhydraatkatabolisme is een fundamenteel proces in de cellulaire stofwisseling waarbij energie uit glucose wordt onttrokken via twee primaire routes: ...

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Microbial Metabolism

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KEY TERMS AND CONCEPTS

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glucose breakdown and atp production

Glucose breakdown is a key part of cell metabolism that lets cells make ATP, the usable form of energy. The process follows two main paths: cellular respiration and fermentation. Both start with glycolysis, which does not require oxygen.

Glycolysis splits one glucose molecule into two molecules of pyruvic acid. It also produces a net gain of two ATP molecules and two NADH molecules. This step sets up the cell to continue with respiration or switch to fermentation, depending on whether oxygen is available.

When oxygen is present, pyruvic acid enters the mitochondria. There it goes through the Krebs cycle and the electron transport chain, or ETC. The Krebs cycle releases carbon dioxide and makes more energy carriers, including NADH and FADH2.

NADH and FADH2 pass electrons to the ETC. The energy from electron movement pumps protons across the mitochondrial membrane and creates a proton gradient. Protons then flow back through ATP synthase, which makes ATP by oxidative phosphorylation. In aerobic respiration, oxygen is the final electron acceptor, and one glucose molecule can produce about 36 to 38 ATP.

Some cells also use anaerobic respiration. In this pathway, molecules such as nitrate or sulfate act as the final electron acceptor instead of oxygen. It makes less ATP than aerobic respiration, but it still allows energy production without oxygen.

When oxygen is not available, cells use fermentation to keep glycolysis going. Fermentation regenerates NAD+ so glycolysis can continue. It changes pyruvic acid into organic products such as lactic acid in animals or ethanol and carbon dioxide in yeast. Because it depends only on glycolysis, fermentation yields just 2 ATP per glucose molecule.

Glucose Breakdown and ATP Production

microbial nutrition

Microbial Energy and Carbon Sources

Microbial energy and carbon sources determine how microorganisms live and grow. These metabolic strategies help microbes survive in many habitats and keep energy moving through ecosystems. They also support nutrient cycling in nature. Microbes are grouped by where they get energy, electrons, and carbon. Phototrophs use light, while chemotrophs use chemical compounds for energy. Lithotrophs take electrons from reduced inorganic substances, and organotrophs take them from organic compounds.

atp and energy production

How Cells Make and Use ATP

ATP is the main energy carrier in cells. It is made of adenosine, which includes adenine and ribose, plus three phosphate groups. The bonds between the phosphate groups hold a large amount of potential energy. When ATP is hydrolyzed, it becomes ADP or AMP and releases energy for cell work. Cells use that energy for many essential tasks. It supports macromolecule synthesis, intracellular transport, and mechanical movement. ATP also acts as an energy manager by linking catabolic and anabolic...

redox reactions

Electron Carriers in Redox Metabolism

Redox reactions move electrons through metabolic pathways in cells. Oxidation is the loss of electrons, and reduction is the gain of electrons. These two steps happen together, which keeps electron flow moving through metabolism. A clear example appears in bacterial metabolism. Glucose is oxidized to carbon dioxide, while oxygen is reduced to water. This shows how one molecule loses electrons as another gains them. Cells use special electron carriers to make these transfers happen.

introduction to metabolism

Metabolism: Energy Use and Biomolecule Synthesis

Metabolism is the set of chemical reactions that keep living cells working. It includes reactions that break down biomolecules and reactions that build them up. These two sides of metabolism work together to support energy balance and cell function. Catabolic pathways break large molecules into smaller parts. Carbohydrates, lipids, and proteins can be broken down into monosaccharides, fatty acids, and amino acids. These reactions release energy, and cells store much of that energy as ATP, or...

carbohydrate catabolism

Glucose breakdown is a key part of cell metabolism that lets cells make ATP, the usable form of energy. The process follows two main paths: cellular respiration and fermentation. Both start with glycolysis, which does not require oxygen. Glycolysis splits one glucose molecule into two molecules of pyruvic acid. It also produces a net gain of two ATP molecules and two NADH molecules. This step sets up the cell to continue with respiration or switch to fermentation, depending on whether oxygen...

glycolysis

Glycolysis and Pyruvate Fate

Glycolysis is a central pathway in glucose catabolism and a major way cells make energy. It is also called the Embden-Meyerhof pathway. This process takes place in the cytoplasm and can work with or without oxygen, which makes it useful in many organisms and conditions. Glycolysis has ten steps and turns one glucose molecule into two pyruvate molecules. It has two phases. In the preparatory phase, the cell uses two ATP to add phosphate groups to glucose and split it into two three-carbon...

other glycolytic pathways

Pentose Phosphate Pathway and Entner-Doudoroff

The pentose phosphate pathway works alongside glycolysis in cells that need both sugar breakdown and building blocks for growth. It handles pentoses, which are five-carbon sugars, and also uses glucose as a starting point. The pathway has two parts, an oxidative phase and a non-oxidative phase. It does not make ATP directly, but its products can feed back into glycolysis when the cell needs them. The oxidative phase mainly makes NADPH, a reduced electron carrier. In this phase,...

cellular respiration

Cellular Respiration: ATP Production Pathways

Cellular respiration is the process cells use to turn glucose into ATP, the main energy molecule in the cell. It depends on oxidation and the transfer of electrons to a separate electron acceptor. This sequence of reactions supports energy production in both aerobic and anaerobic settings. Glycolysis is the first step. It takes place in the cytoplasm of both prokaryotic and eukaryotic cells. One glucose molecule is broken into two pyruvate molecules, and the cell gains a net 2 ATP and 2 NADH.

electron transport chain components

Electron Transport Chain and ATP Production

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chemiosmosis and atp synthesis

Electron Transport Chain Powers ATP Output

The electron transport chain powers ATP production during cellular respiration. It sits in the inner mitochondrial membrane and moves high-energy electrons from NADH and FADH2 to molecular oxygen, the final electron acceptor. As electrons move through the chain, protons are pushed across the membrane to build the gradient needed for ATP synthesis. Electrons from NADH enter the chain at Complex I, also called NADH: ubiquinone oxidoreductase. In prokaryotes, this step helps pump protons from the...

respiration pathways

TCA Cycle and Energy Pathways

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microbial fermentation

Fermentation Products in Microbes

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metabolism of chemolithotrophs

How Chemolithotrophs Make ATP

Chemolithotrophs make ATP by using inorganic chemicals as an energy source. They oxidize molecules such as hydrogen gas, ammonia, reduced sulfur compounds, and ferrous iron. Instead of relying on organic carbon like heterotrophs, they move electrons from these inorganic donors into the electron transport chain, or ETC. That electron flow builds a proton motive force, or PMF. The PMF drives ATP synthesis through oxidative phosphorylation. Because inorganic electron donors usually release less...

amino acid catabolism

Microbes Use Proteins for Energy

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lipid catabolism

How Microbes Break Down Fats for Energy

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oxygenic photosynthesis

How Plants Make Oxygen and ATP

Oxygenic photosynthesis is the process plants, algae, and cyanobacteria use to capture light energy and turn it into chemical energy. It uses water as the source of electrons and releases molecular oxygen, or O2. The process also produces ATP and NADPH, which cells need for later energy use and carbon fixation. The main reactions happen in the thylakoid membranes, where chlorophyll pigments absorb light. In cyanobacteria, these membranes come from folds in the plasma membrane. Two photosystems...

anoxygenic photosynthesis

Bacterial Light Capture Without Oxygen

Anoxygenic photosynthesis is a bacterial way to capture light energy without making oxygen. It supports carbon fixation, but it does not use water as the electron donor. Instead, these phototrophs use other electron donors such as hydrogen sulfide, elemental sulfur, thiosulfate, or organic compounds. This process is carried out by several groups of bacteria, including purple bacteria, green sulfur bacteria, heliobacteria, and other anoxygenic phototrophs. These organisms have evolved a...

biosynthesis in bacteria

How Bacteria Build Key Macromolecules

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carbon-dioxide fixation

Microbial Carbon Fixation Pathways

Microbial carbon fixation pathways let prokaryotes turn carbon dioxide into organic molecules. This process supports biosynthesis, helps sustain ecosystems, and plays a role in the global carbon cycle. It also has industrial uses in carbon capture and bioproduct synthesis. Autotrophic organisms depend on this process to use CO2 as a carbon source in many environments. The Calvin cycle is the most common carbon fixation pathway. Cyanobacteria and other autotrophic prokaryotes use it, and it...

biosynthesis of polysaccharides

Activated Sugars for Polysaccharide Synthesis

Activated sugars drive polysaccharide synthesis in cells. Glycogen and starch are built from nucleoside diphosphate sugars, mainly uridine diphosphate glucose (UDPG) and adenosine diphosphate glucose (ADPG). These sugar donors act as high-energy intermediates in carbohydrate metabolism and biosynthesis. UDPG supports glycogen synthesis in animals and many bacteria. It forms when glucose-1-phosphate reacts with uridine triphosphate (UTP). UDP-glucose pyrophosphorylase catalyzes this reaction.

inorganic nitrogen assimilation

Nitrogen Uptake by Microbes

Nitrogen uptake by microbes is essential for making proteins, nucleic acids, and other cell parts. Many bacteria and archaea take in nitrogen as nitrate or ammonia. They then convert it into forms that can be built into biomolecules. When nitrate enters a cell, it goes through assimilatory nitrate reduction. This is a two-step process. First, nitrate reductase changes nitrate to nitrite using NADH or FAD as an electron donor, depending on environmental and cellular conditions. Then nitrite...

sulfur assimilation

Sulfur Uptake and Cysteine Synthesis

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amino acid biosynthetic pathways

Amino Acid Building from Cell Metabolites

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biosynthesis of nucleic acids

Nucleotide Building Blocks for DNA and RNA

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biosynthesis of lipids

How Membrane Lipids Vary Across Life

Membrane lipids vary across Bacteria, Archaea, and Eukarya, and these differences help cells survive in different environments. The three domains of life make lipids through distinct biosynthetic pathways. Those pathways create membranes with different stability, permeability, and flexibility. Bacteria and eukaryotes both build fatty acid-based lipids from acetyl-CoA and malonyl-CoA. The pathway includes condensation, reduction, and dehydration steps. Bacteria use a type II fatty acid...

formation of lipopolysaccharides

Lipopolysaccharides and Gram-Negative Defense

Lipopolysaccharides (LPS) are important parts of the outer membrane of Gram-negative bacteria. They help stabilize the membrane and help protect bacteria from host immune responses. LPS has three main parts: lipid A, a core oligosaccharide, and an O antigen. LPS biosynthesis and assembly depend on a coordinated set of enzymes and transport steps. The molecule is also known as an endotoxin. It can activate Toll-like receptor 4 (TLR4) in the host and trigger strong immune responses. In severe...

key terms and concepts

See how glycolysis, cellular respiration, and fermentation turn glucose into ATP. Learn why oxygen changes the pathway and how cells keep making energy.

Glucose Breakdown and ATP Production | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Glucose Breakdown and ATP Production

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