Name: cellular respiration: atp production pathways
Uploaded: 2025-06-12T09:34:08.000Z
Duration: 1 min 18 s
Channel: JoVE

Hücresel solunum, harici bir elektron alıcısı kullanarak moleküllerin oksidasyonu yoluyla ATP üreten biyokimyasal bir süreçtir. Glikoliz ile başlar, ATP ve NADH üretirken glikozu piruvata dönüştürür. Pirüvat, prokaryotların sitoplazmasında veya ökaryotların mitokondriyal matrisinde meydana gelen Krebs döngüsüne girerek NADH ve FADH2 üretir. Bu taşıyıcılardan gelen elektronlar, prokaryotların plazma zarında ve ökaryotların iç mitokondriyal zarında bulunan elektron taşıma zincirinden geçer ve oksidatif fosforilasyon yoluyla ATP üretir. Aerobik solunum, elektron alıcısı olarak oksijen kullanır ve prokaryotlarda glikoz molekülü başına 38 ATP'ye kadar üretebilir. Ökaryotlarda net verim yaklaşık 30 ila 32 ATP'dir, çünkü NADH mekiği sırasında bir miktar enerji tüketilir. Bazı prokaryotlar ve ökaryotlar, daha az ATP verimine sahip elektron alıcısı olarak nitrat veya sülfat gibi alternatif elektron alıcılarını kullanan anaerobik solunuma tabi tutulur.

solunum

Cellular Respiration

H&#252;cresel solunum, h&#252;crelerin adenozin trifosfat (ATP) &#252;retmek i&#231;in organik maddelerden, &#246;zellikle glikozdan, enerji elde etti&#287;i kritik bir metabolik s&#252;re&#231;tir. Bu s&#252;re&#231;, substratlar&#305;n oksidasyonunu ve elektronlar&#305;n ayr&#305; bir elektron al&#305;c&#305;s&#305;na transferini i&#231;erir ve bir dizi biyokimyasal reaksiyon arac&#305;l&#305;&#287;&#305;yla ATP sentezine yard&#305;m eder..
Glikoliz: &#304;lk A&#351;ama
Glikoliz, h&#252;cresel solunumun ilk a&#351;amas&#305;d&#305;r ve hem prokaryotik hem de &#246;karyotik h&#252;crelerin sitoplazmas&#305;nda ger&#231;ekle&#351;ir. Bir glikoz (C_6H_12O_6) molek&#252;l&#252;n&#252;n iki piruvat (C_3H_4O_3) molek&#252;l&#252;ne par&#231;alanmas&#305;n&#305; i&#231;erir ve net olarak 2 ATP ve 2 NADH kazan&#305;m&#305; sa&#287;lar. Bu s&#252;re&#231; oksijen gerektirmez ve hem aerobik hem de anaerobik solunum i&#231;in haz&#305;rl&#305;k ad&#305;m&#305; olarak i&#351;lev g&#246;r&#252;r.
Krebs D&#246;ng&#252;s&#252;: Elektron Ta&#351;&#305;y&#305;c&#305;lar&#305;n&#305;n &#220;retimi
Piruvat, dekarboksilasyon ad&#305; verilen &#246;nemli bir s&#252;re&#231;ten ge&#231;erek asetil-CoA&#8217;ya d&#246;n&#252;&#351;&#252;r. Bu yeni olu&#351;an asetil-CoA, Krebs d&#246;ng&#252;s&#252;ne (sitrik asit d&#246;ng&#252;s&#252; veya trikarboksilik asit d&#246;ng&#252;s&#252; olarak da bilinir) girer. Bu karma&#351;&#305;k biyokimyasal reaksiyonlar dizisi, prokaryotlarda sitoplazmada, &#246;karyotlarda ise mitokondriyal matriste ger&#231;ekle&#351;ir.
Asetil-CoA, Krebs d&#246;ng&#252;s&#252;nden ge&#231;erken enerji &#252;retiminde hayati bir rol oynar. &#304;&#351;lenen her asetil-CoA molek&#252;l&#252; i&#231;in d&#246;ng&#252;, &#252;&#231; NADH molek&#252;l&#252;, bir FADH_2 molek&#252;l&#252; ve bir GTP &#252;retir. NADH ve FADH_2 gibi elektron ta&#351;&#305;y&#305;c&#305;lar&#305;, sonraki reaksiyonlarda ATP sentezini y&#246;nlendirmek i&#231;in gereklidir. Ayr&#305;ca, bu s&#252;re&#231;te karbondioksit (CO_2) bir yan &#252;r&#252;n olarak sal&#305;n&#305;r ve h&#252;crenin genel metabolik faaliyetlerine katk&#305;da bulunur.
Elektron Ta&#351;&#305;ma Zinciri ve Oksidatif Fosforilasyon
Elektron ta&#351;&#305;ma zinciri (ETZ), prokaryotlarda plazma membran&#305;nda, &#246;karyotlarda ise i&#231; mitokondriyal membranda yer al&#305;r. NADH ve FADH&#8322;&#8217;den gelen elektronlar, bir dizi protein kompleksi arac&#305;l&#305;&#287;&#305;yla transfer edilerek membran boyunca bir proton gradyan&#305; olu&#351;turur. Protonlar&#305;n ATP sentaz &#252;zerinden geri ak&#305;&#351;&#305;, ADP&#8217;nin ATP&#8217;ye fosforilasyonunu sa&#287;lar. Aerobik solunumda, oksijen son elektron al&#305;c&#305;s&#305; olarak i&#351;lev g&#246;r&#252;r ve su (H_2O) olu&#351;turur.
ATP Verimi ve Alternatif Elektron Al&#305;c&#305;lar
Aerobik solunum, prokaryotlarda glikoz ba&#351;&#305;na 38 ATP&#8217;ye kadar &#252;retim sa&#287;larken, &#246;karyotlarda NADH&#8217;nin mitokondriye ta&#351;&#305;nmas&#305;yla ili&#351;kili enerji maliyetleri nedeniyle net ATP &#252;retimi yakla&#351;&#305;k 30&#8211;32&#8217;dir. Anaerobik solunumda, prokaryotlar ve baz&#305; &#246;karyotlar, nitrat (NO_3^-), s&#252;lfat (SO_4^2-) veya karbondioksit (CO_2) gibi alternatif elektron al&#305;c&#305;lar&#305; kullan&#305;r ve bu al&#305;c&#305;lar&#305;n proton gradyan&#305; olu&#351;turmadaki d&#252;&#351;&#252;k verimlili&#287;i nedeniyle genellikle glikoz ba&#351;&#305;na yakla&#351;&#305;k 2 ATP &#252;retir.
H&#252;cresel solunum, ATP &#252;retimi yoluyla h&#252;cresel i&#351;levleri s&#252;rd&#252;rmek i&#231;in organizmalar&#305;n enerji metabolizmas&#305; a&#231;&#305;s&#305;ndan vazge&#231;ilmezdir. Elektron al&#305;c&#305;s&#305;n&#305;n verimlili&#287;i ve se&#231;imi, farkl&#305; ortamlardaki organizmalar&#305;n enerji verimini ve metabolik adaptasyonlar&#305;n&#305; belirler.

Solunum

H&#252;cresel solunum, h&#252;crelerin adenozin trifosfat (ATP) &#252;retmek i&#231;in organik maddelerden, &#246;zellikle glikozdan, enerji elde ...

Education

JoVE Core

Microbiology

Mikrobiyoloji

Unit

Birim

Microbial Metabolism

Mikrobiyal Metabolizma

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

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. Glycolysis does not require oxygen, so it can support both aerobic and anaerobic respiration.

Pyruvate then undergoes decarboxylation and becomes acetyl-CoA. Acetyl-CoA enters the Krebs cycle, also called the citric acid cycle or tricarboxylic acid cycle. In prokaryotes, this cycle occurs in the cytoplasm. In eukaryotes, it occurs in the mitochondrial matrix. Each acetyl-CoA produces 3 NADH, 1 FADH2, and 1 GTP. The cycle also releases carbon dioxide as a byproduct.

The electron transport chain, or ETC, uses the NADH and FADH2 made earlier. In prokaryotes, the ETC is in the plasma membrane. In eukaryotes, it is in the inner mitochondrial membrane. Electrons move through protein complexes and create a proton gradient across the membrane. ATP synthase uses the return flow of protons to convert ADP into ATP. In aerobic respiration, oxygen is the final electron acceptor, and water forms.

Aerobic respiration can yield up to 38 ATP per glucose in prokaryotes. In eukaryotes, the net yield is about 30 to 32 ATP because energy is used to move NADH into mitochondria. Some organisms also use anaerobic respiration. In that pathway, alternative electron acceptors such as nitrate, sulfate, or carbon dioxide are used. This form makes much less ATP, usually around 2 ATP per glucose, because these acceptors build a weaker proton gradient. Cellular respiration is therefore essential for ATP production and for the energy metabolism that keeps cells functioning.

Cellular Respiration: ATP Production Pathways

cellular-respiration-atp-production-pathways

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atp and energy production

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glycolysis

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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

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cellular respiration

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...

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Electron Transport Chain Powers ATP Output

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Fermentation Products in Microbes

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How Chemolithotrophs Make ATP

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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

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...

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How Bacteria Build Key Macromolecules

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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

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Lipopolysaccharides and Gram-Negative Defense

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key terms and concepts

Learn how cells make ATP through glycolysis, the Krebs cycle, and the electron transport chain, plus how aerobic and anaerobic respiration differ.

Cellular Respiration: ATP Production Pathways | 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

Cellular Respiration: ATP Production Pathways

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