Name: how chemolithotrophs make atp
Uploaded: 2025-06-12T09:35:21.000Z
Duration: 1 min 15 s
Channel: JoVE

Los quimiolitótrofos obtienen energía oxidando compuestos inorgánicos como el gas hidrógeno, el amoníaco, los sulfuros y el hierro ferroso. Los electrones de estas moléculas entran en la cadena de transporte de electrones, impulsando la producción de ATP a través de la fosforilación oxidativa a través de la ATP sintasa. Los donantes inorgánicos liberan menos energía que las moléculas orgánicas. Como resultado, se bombean menos protones a través de la membrana, lo que resulta en una menor producción de ATP. El oxígeno es el aceptor de electrones más común, pero los quimiolitótrofos también pueden usar nitrato, sulfato o dióxido de carbono en condiciones anaeróbicas. La mayoría de los quimiolitótrofos son autótrofos y utilizan su energía para fijar dióxido de carbono y sintetizar moléculas orgánicas. Algunos de ellos dependen del flujo inverso de electrones para generar potencia reductora en forma de NADH. Esto ocurre cuando el donante de electrones tiene un potencial redox más alto que el NAD+. En tales casos, la energía de la fuerza motriz del protón se utiliza para empujar los electrones contra el gradiente para reducir NAD+ a NADH.

vías de conservación de energía

Metabolism of Chemolithotrophs

Los quimiolit&#243;trofos son microorganismos que obtienen energ&#237;a mediante la oxidaci&#243;n de mol&#233;culas inorg&#225;nicas como el hidr&#243;geno molecular (H_2), el amon&#237;aco (NH_3), compuestos de azufre reducido (H_2S, S^2-) y el ion ferroso (Fe^2+). A diferencia de los organismos heter&#243;trofos que dependen del carbono org&#225;nico, los quimiolit&#243;trofos transfieren electrones desde estos donadores inorg&#225;nicos a la cadena de transporte de electrones (ETC), generando una fuerza prot&#243;n-motriz (PMF) que impulsa la s&#237;ntesis de ATP a trav&#233;s de la fosforilaci&#243;n oxidativa. Sin embargo, dado que los donadores de electrones inorg&#225;nicos generalmente proporcionan menos energ&#237;a que las mol&#233;culas org&#225;nicas, los quimiolit&#243;trofos deben oxidar grandes cantidades de material inorg&#225;nico para mantener su crecimiento.
La eficiencia de la producci&#243;n de energ&#237;a en los quimiolit&#243;trofos depende del potencial redox de sus donadores y aceptores de electrones. El ox&#237;geno (O_2) es el aceptor final de electrones m&#225;s utilizado, ya que posee un potencial redox altamente positivo, lo que maximiza el rendimiento energ&#233;tico. No obstante, algunos quimiolit&#243;trofos pueden utilizar aceptores alternativos como el nitrato (NO_3^-), el sulfato (SO_4^2-) o el di&#243;xido de carbono (CO_2) en condiciones anaerobicas. Dado que las mol&#233;culas inorg&#225;nicas proporcionan menos energ&#237;a que los sustratos org&#225;nicos, las cadenas de transporte de electrones en los quimiolit&#243;trofos a menudo bombean menos protones a trav&#233;s de la membrana, lo que se traduce en una menor producci&#243;n de ATP en comparaci&#243;n con los organismos heter&#243;trofos.
La mayor&#237;a de los quimiolit&#243;trofos son aut&#243;trofos, lo que significa que utilizan ATP y poder reductor para fijar CO_2 y sintetizar mol&#233;culas org&#225;nicas para su crecimiento. Sin embargo, algunos donadores de electrones inorg&#225;nicos, como Fe^2+ y NO_2^-, tienen potenciales redox m&#225;s altos que el par NAD^+/NADH, lo que hace termodin&#225;micamente desfavorable reducir NAD^+ a NADH directamente. Para superar esta limitaci&#243;n, muchos quimiolit&#243;trofos utilizan el flujo electr&#243;nico inverso, un proceso que consume energ&#237;a y que fuerza a los electrones a moverse contra el gradiente termodin&#225;mico para producir NADH el cual es esencial para las reacciones biosint&#233;ticas.
Los quimiolit&#243;trofos se clasifican en funci&#243;n de sus donadores de electrones preferidos. Las bacterias oxidadoras de hidr&#243;geno utilizan H_2 como fuente de energ&#237;a y transfieren electrones al NAD^+ o a la ETC mediante enzimas hidrogenasas. Las bacterias nitrificantes desempe&#241;an un papel crucial en el ciclo del nitr&#243;geno al oxidar amon&#237;aco (NH_3) a nitrito (NO_2^-) y luego a nitrato (NO_3^-), en un proceso conocido como nitrificaci&#243;n. Las bacterias oxidadoras de azufre metabolizan compuestos de azufre como H_2S y S^2-, generando sulfato (SO_4^2-) y ATP mediante fosforilaci&#243;n oxidativa y fosforilaci&#243;n a nivel de sustrato. Adem&#225;s, las bacterias anammox llevan a cabo la oxidaci&#243;n anaerobia del amonio, un proceso &#250;nico que convierte NH_4^+ y NO_2^- en gas nitr&#243;geno(N_2), contribuyendo a la p&#233;rdida de nitr&#243;geno en ambientes acu&#225;ticos.
Los quimiolitotrofos desempe&#241;an un papel fundamental en los ciclos biogeoqu&#237;micos globales, especialmente en los del nitr&#243;geno, el azufre y el hierro. Contribuyen a la transformaci&#243;n y reciclaje de nutrientes esenciales en los ecosistemas, influyendo en la qu&#237;mica del suelo y del agua. Adem&#225;s, estos microorganismos se utilizan en diversas aplicaciones industriales y medioambientales, como la biorremediaci&#243;n, la biolixiviaci&#243;n y el tratamiento de aguas residuales. Su capacidad para prosperar en entornos extremos, incluidos respiraderos hidrotermales de aguas profundas y zonas de drenaje &#225;cido de minas, resalta su versatilidad metab&#243;lica y su relevancia ecol&#243;gica.

Vías de conservación de energía

Los quimiolit&#243;trofos son microorganismos que obtienen energ&#237;a mediante la oxidaci&#243;n de mol&#233;culas inorg&#225;nicas como el ...

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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 energy than organic molecules, chemolithotrophs often need to oxidize large amounts of inorganic material to support growth.

Their energy yield depends on the redox potential of the electron donor and acceptor. Oxygen is the most common terminal electron acceptor because it has a highly positive redox potential and gives the best energy yield. Some chemolithotrophs can also use nitrate, sulfate, or carbon dioxide as acceptors when oxygen is not available.

These microbes usually make less ATP than heterotrophs because their ETCs often pump fewer protons across the membrane. Most chemolithotrophs are autotrophs, so they use ATP and reducing power to fix carbon dioxide and build organic molecules. Some donors, such as Fe2+ and NO2-, have a higher redox potential than the NAD+/NADH pair, so direct NADH formation is not favorable.

To solve this problem, many chemolithotrophs use reverse electron flow. This process spends energy to push electrons against the normal gradient and make NADH for biosynthesis. Hydrogen-oxidizing bacteria use H2 and transfer electrons with hydrogenase enzymes. Nitrifying bacteria oxidize ammonia to nitrite and then nitrate, which is called nitrification and is important in the nitrogen cycle.

Sulfur-oxidizing bacteria use compounds such as H2S and S2- and produce sulfate. They can make ATP through both oxidative phosphorylation and substrate-level phosphorylation. Anammox bacteria carry out anaerobic ammonia oxidation and convert NH4+ and NO2- into nitrogen gas, which contributes to nitrogen loss in aquatic environments.

Chemolithotrophs are key parts of the nitrogen, sulfur, and iron cycles. They help recycle nutrients and shape soil and water chemistry. They are also used in bioremediation, bioleaching, and wastewater treatment, and many can live in extreme places such as deep-sea hydrothermal vents and acidic mine drainage sites.

How Chemolithotrophs Make ATP

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Microbial Energy and Carbon Sources

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atp and energy production

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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...

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glycolysis

Glycolysis and Pyruvate Fate

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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

The electron transport chain helps cells make ATP by moving electrons through membrane protein complexes. In eukaryotic cells, it sits in the inner mitochondrial membrane. In prokaryotic cells, it is found in the plasma membrane and can differ in the number and type of complexes, depending on the organism and its environment. The chain uses several electron carriers to pass electrons along in redox reactions, which are reactions that involve oxidation and reduction. These carriers include...

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

Cellular respiration uses the TCA cycle, also called the Krebs cycle, to help cells make usable energy from organic molecules. This pathway is a central part of aerobic respiration and also supports biosynthesis. It links the breakdown of food molecules to the cell's energy needs. Pyruvate from glycolysis enters this process first. The pyruvate dehydrogenase complex converts pyruvate into acetyl-CoA through oxidative decarboxylation. This step produces one NADH and one carbon dioxide molecule.

microbial fermentation

Fermentation Products in Microbes

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metabolism of chemolithotrophs

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

Microbes can use proteins as a carbon and energy source, especially when polysaccharides or lipids are scarce. But proteins are too large to pass through the plasma membrane on their own. To solve this, microbes secrete extracellular proteases and peptidases that break proteins into peptides. The peptides are then transported into the cell, where intracellular proteases cut them into free amino acids. Once amino acids are available, microbes break them down in two main ways: deamination and...

lipid catabolism

How Microbes Break Down Fats for Energy

Microbes break down triglycerides and fatty acids to make energy. Triglycerides are important long-term energy storage molecules in microorganisms. Lipases hydrolyze, or split with water, triglycerides into glycerol and free fatty acids. Each product then enters a different metabolic route that helps the cell make ATP, the main energy currency. Glycerol metabolism begins after glycerol is released from triglyceride hydrolysis. Glycerol kinase adds a phosphate group to form glycerol-3-phosphate.

oxygenic photosynthesis

How Plants Make Oxygen and ATP

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anoxygenic photosynthesis

Bacterial Light Capture Without Oxygen

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How Bacteria Build Key Macromolecules

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Microbial Carbon Fixation Pathways

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biosynthesis of polysaccharides

Activated Sugars for Polysaccharide Synthesis

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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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Nucleotide Building Blocks for DNA and RNA

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biosynthesis of lipids

How Membrane Lipids Vary Across Life

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Lipopolysaccharides and Gram-Negative Defense

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key terms and concepts

Learn how chemolithotrophs use inorganic molecules like hydrogen, ammonia, sulfur, and iron to make ATP, fix CO2, and drive nitrogen and sulfur cycles.

How Chemolithotrophs Make ATP | 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

How Chemolithotrophs Make ATP

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