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

Oddychanie komórkowe to proces biochemiczny, który generuje ATP poprzez utlenianie cząsteczek przy użyciu zewnętrznego akceptora elektronów. Rozpoczyna się od glikolizy, przekształcania glukozy w pirogronian podczas produkcji ATP i NADH. Pirogronian wchodzi w cykl Krebsa, występując w cytoplazmie prokariontów lub w macierzy mitochondrialnej eukariontów, generując NADH i FADH2. Elektrony z tych nośników przechodzą przez łańcuch transportu elektronów, znajdujący się w błonie plazmatycznej prokariontów i wewnętrznej błonie mitochondrialnej eukariontów, wytwarzając ATP poprzez fosforylację oksydacyjną. Oddychanie tlenowe wykorzystuje tlen jako akceptor elektronów i może wytwarzać do 38 ATP na cząsteczkę glukozy u prokariontów. U eukariontów wydajność netto wynosi około 30 do 32 ATP, ponieważ część energii jest zużywana podczas transportu NADH. Niektóre prokariota i eukarionty przechodzą oddychanie beztlenowe, które wykorzystuje alternatywne akceptory elektronów, takie jak azotan lub siarczan, jako akceptor elektronów z mniejszą wydajnością ATP.

oddychanie

Cellular Respiration

Oddychanie kom&#243;rkowe to kluczowy proces metaboliczny, dzi&#281;ki kt&#243;remu kom&#243;rki pozyskuj&#261; energi&#281; z substancji organicznych, g&#322;&#243;wnie glukozy, w celu wytworzenia trifosforanu adenozyny (ATP). Proces ten obejmuje utlenianie substrat&#243;w i przekazywanie elektron&#243;w do oddzielnego akceptora elektron&#243;w, umo&#380;liwiaj&#261;c syntez&#281; ATP poprzez sekwencj&#281; reakcji biochemicznych.
Glikoliza: etap pocz&#261;tkowy
Glikoliza to pierwszy etap oddychania kom&#243;rkowego, zachodz&#261;cy w cytoplazmie zar&#243;wno kom&#243;rek prokariotycznych, jak i eukariotycznych. Polega na rozk&#322;adzie jednej cz&#261;steczki glukozy (C_6 H_12 O_6) do dw&#243;ch cz&#261;steczek pirogronianu (C_3 H_4 O_3), przynosz&#261;c zysk netto w postaci 2 cz&#261;steczek ATP i 2 cz&#261;steczek NADH. Proces ten nie wymaga obecno&#347;ci tlenu i stanowi etap przygotowawczy zar&#243;wno dla oddychania tlenowego, jak i beztlenowego.
Cykl Krebsa: generowanie przeno&#347;nik&#243;w elektron&#243;w
Pirogronian podlega kluczowemu procesowi dekarboksylacji, w wyniku kt&#243;rego przekszta&#322;ca si&#281; w acetylo-CoA. Nowo powsta&#322;y acetylo-CoA wchodzi nast&#281;pnie w cykl Krebsa, zwany r&#243;wnie&#380; cyklem kwasu cytrynowego lub cyklem kwasu trikarboksylowego. Z&#322;o&#380;ony szereg reakcji biochemicznych zachodzi w cytoplazmie prokariont&#243;w oraz w macierzy mitochondrialnej eukariont&#243;w.
W miar&#281; przechodzenia acetylo-CoA przez cykl Krebsa, odgrywa on istotn&#261; rol&#281; w produkcji energii. Dla ka&#380;dej cz&#261;steczki acetylo-CoA cykl generuje trzy cz&#261;steczki NADH, jedn&#261; cz&#261;steczk&#281; FADH_2 oraz jedn&#261; cz&#261;steczk&#281; GTP. Te przeno&#347;niki elektron&#243;w, NADH i FADH_2, s&#261; niezb&#281;dne do nap&#281;dzania syntezy ATP w kolejnych etapach. Dodatkowo, w trakcie tego procesu uwalniany jest dwutlenek w&#281;gla (CO_2) jako produkt uboczny, kt&#243;ry uczestniczy w ca&#322;kowitej aktywno&#347;ci metabolicznej kom&#243;rki.
&#321;a&#324;cuch transportu elektron&#243;w i fosforylacja oksydacyjna
&#321;a&#324;cuch transportu elektron&#243;w (ETC) znajduje si&#281; w b&#322;onie plazmatycznej u prokariont&#243;w, natomiast u eukariont&#243;w &#8212; w wewn&#281;trznej b&#322;onie mitochondrialnej. Elektrony pochodz&#261;ce z NADH i FADH_2 s&#261; przekazywane przez szereg kompleks&#243;w bia&#322;kowych, co prowadzi do wytworzenia gradientu protonowego przez b&#322;on&#281;. Powr&#243;t proton&#243;w przez syntaz&#281; ATP nap&#281;dza fosforylacj&#281; ADP do ATP. W oddychaniu tlenowym tlen pe&#322;ni rol&#281; ko&#324;cowego akceptora elektron&#243;w, tworz&#261;c wod&#281; (H_2O).
Wydajno&#347;&#263; ATP i alternatywne akceptory elektron&#243;w
Oddychanie tlenowe mo&#380;e dostarczy&#263; do 38 cz&#261;steczek ATP z jednej cz&#261;steczki glukozy u prokariont&#243;w, natomiast u eukariont&#243;w produkcja netto wynosi oko&#322;o 30&#8211;32 ATP ze wzgl&#281;du na koszty energetyczne zwi&#261;zane z transportem NADH do mitochondri&#243;w. W oddychaniu beztlenowym prokarionty i niekt&#243;re eukarionty wykorzystuj&#261; alternatywne akceptory elektron&#243;w, takie jak azotan (NO_3^-), siarczan (SO_4^2-) lub dwutlenek w&#281;gla (CO_2), co skutkuje znacznie mniejsz&#261; produkcj&#261; ATP &#8212; zazwyczaj oko&#322;o 2 ATP na cz&#261;steczk&#281; glukozy &#8212; ze wzgl&#281;du na ni&#380;sz&#261; efektywno&#347;&#263; tych akceptor&#243;w w generowaniu gradientu protonowego.
Oddychanie kom&#243;rkowe jest niezb&#281;dne dla metabolizmu energetycznego, umo&#380;liwiaj&#261;c organizmom podtrzymanie funkcji kom&#243;rkowych dzi&#281;ki produkcji ATP. Wydajno&#347;&#263; energetyczna oraz wyb&#243;r akceptora elektron&#243;w determinuj&#261; ilo&#347;&#263; wytworzonej energii i adaptacje metaboliczne organizm&#243;w w r&#243;&#380;nych warunkach &#347;rodowiskowych.

Oddychanie

Oddychanie kom&#243;rkowe to kluczowy proces metaboliczny, dzi&#281;ki kt&#243;remu kom&#243;rki pozyskuj&#261; energi&#281; z substancji organicznych, ...

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Microbial Metabolism

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KEY TERMS AND CONCEPTS

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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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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

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Electron Transport Chain Powers ATP Output

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How Chemolithotrophs Make ATP

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Microbes Use Proteins for Energy

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How Microbes Break Down Fats for Energy

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How Plants Make Oxygen and ATP

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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

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sulfur assimilation

Sulfur Uptake and Cysteine Synthesis

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Amino Acid Building from Cell Metabolites

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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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