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Related Concept Videos

Oxidation of Phenols to Quinones01:17

Oxidation of Phenols to Quinones

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In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
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Redox Reactions01:27

Redox Reactions

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Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
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Redox Reactions01:24

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Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
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Mitochondria01:37

Mitochondria

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Mitochondria are eukaryotic cellular organelles that are known to produce energy through a process called oxidative phosphorylation. Besides their primary function, mitochondria are involved in various cellular processes, including cell growth, differentiation, signaling, metabolism, and senescence. Age-related changes cause a decline in mitochondrial quality and integrity due to increased mitochondrial mutations and oxidative damage. Thus, aging can severely impact mitochondrial functions,...
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Electron Transport Chain: Complex III and IV01:43

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During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
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Electron Transport Chain: Complex I and II01:46

Electron Transport Chain: Complex I and II

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The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
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Lipid Supplementation for Longevity and Gene Transcriptional Analysis in Caenorhabditis elegans
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Coenzyme Q redox signalling and longevity.

Filippo Scialo1, Alberto Sanz2

  • 1Dipartimento di Scienze Mediche Traslazionali, Università della Campania "Luigi Vanvitelli", 80131, Napoli, Italy.

Free Radical Biology & Medicine
|January 15, 2021
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Summary
This summary is machine-generated.

Mitochondrial Reactive Oxygen Species (mtROS) are vital redox messengers, not just toxic byproducts. Understanding their generation in aging mitochondria is key to preserving cellular health and function.

Keywords:
AgeingCoenzyme QComplex IComplex IIIMitochondriaROSRedox signalling

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Area of Science:

  • Cellular Biology
  • Mitochondrial Function
  • Redox Signaling

Background:

  • Mitochondria generate energy (ATP) and Reactive Oxygen Species (ROS).
  • Mitochondrial ROS (mtROS) were historically viewed as harmful byproducts linked to aging and disease.
  • Emerging evidence highlights mtROS as crucial redox messengers regulating cell fate and homeostasis.

Purpose of the Study:

  • To review the generation of mtROS in both young and aged mitochondria.
  • To elucidate the roles of mtROS derived from respiratory Complex I (CI) and Complex III (CIII) in physiological and pathological processes.
  • To discuss the accumulation of damaged mitochondria during aging and strategies for preserving mitochondrial redox signaling.

Main Methods:

  • Review of existing literature on mitochondrial ROS generation.
  • Analysis of the roles of Coenzyme Q (CoQ) redox state and proton motive force (pmf) in mtROS production by CI and CIII.
  • Discussion of mechanisms underlying mitochondrial dysfunction and ROS production during aging.

Main Results:

  • mtROS production by CI and CIII is modulated by the CoQ pool and pmf.
  • Aging is associated with accumulation of defective mitochondria producing excessive mtROS, leading to oxidative stress and disrupted redox signaling.
  • mtROS play critical roles in regulating cellular homeostasis and are implicated in various physiological and pathological conditions.

Conclusions:

  • mtROS are essential signaling molecules, with their production tightly regulated by mitochondrial respiration.
  • Mitochondrial dysfunction and increased mtROS production during aging contribute to cellular damage and disease.
  • Preserving mitochondrial redox signaling is crucial for mitigating age-related decline and maintaining cellular health.