This pathophysiology diagram illustrates mitochondrial bioenergetics, specifically the electron transport chain (ETC), ATP synthesis, and the generation of reactive oxygen/nitrogen species (ROS/RNS). The upper portion details the inner mitochondrial membrane containing Complexes I through V. Complex I (NADH ubiquinone reductase) and Complex II (Succinate dehydrogenase) receive electrons from NADH and FADH2, respectively. Electrons flow through ubiquinone (CoQ) and cytochrome c (Cyt c) to Complex IV (Cytochrome c oxidase), which reduces O2 to H2O. Complexes I, III, and IV pump protons (H+) into the intermembrane space, creating a gradient that drives Complex V (F0F1 ATP Synthase) to convert ADP + Pi into ATP. ATP then exits to the cytosol via the VDAC channel. The lower section depicts oxidative stress pathways: O2 is converted to superoxide (•O2-) by oxidases or mitochondrial leakage. Superoxide is neutralized by Superoxide Dismutase (SOD) into H2O2, which Catalase (CAT) or the GSH/GSSG cycle converts to water. Alternatively, superoxide reacts with NO to form peroxynitrite (ONOO-) or leads to hydroxyl radicals (•OH), resulting in oxidative damage, mtDNA mutations, and mitochondrial dysfunction.

A pathophysiology diagram illustrating the mitochondrial oxidative phosphorylation (OXPHOS) system and its therapeutic inhibitors. The top schematic shows the inner mitochondrial membrane containing the Electron Transport Chain (ETC) complexes I through IV, Coenzyme Q (CoQ), and Cytochrome c (Cyt c), alongside ATP synthase (Complex V). It depicts the flow of electrons (2e-) from NADH and FADH2, the pumping of protons (H+) into the intermembrane space, and the final reduction of oxygen to water. Complex V is shown utilizing the proton gradient to convert ADP to ATP. The lower section identifies two pharmacological strategies for ATP depletion in cancer cells: 'Targeting OXPHOS complexes' using drugs like Pyrvinium pamoate, Atovaquone, Niclosamide, and Irinotecan; and 'Targeting Mitochondrial Biogenesis' using antibiotics such as Doxycycline, Tigecycline, and Azithromycin. Inhibitory arrows indicate these drugs disrupt mitochondrial function to target cancer stem cells (CSCs).

A pathophysiology diagram illustrating the mitochondrial respiratory chain dysfunction resulting from the disassembly of supercomplexes (SCs). The visual compares two states: an organized supercomplex and a disassembled state. On the left, Complex I (CI, green), Complex III (CIII, blue), and Complex IV (CIV, orange) are closely associated in a functional supercomplex, with Coenzyme Q (CoQ) and Cytochrome c (Cyt c) in close proximity to facilitate efficient electron transfer. A red 'X' on CIII signifies a defect. Following a 'Disassembly' arrow, the right side depicts the complexes separated. This structural breakdown leads to a longer diffusion distance for CoQ and Cyt c, represented by their wider dispersion. The educational focus is on the consequences of SC disassembly: increased production of Reactive Oxygen Species (ROS), indicated by larger blue arrows; decreased efficiency of electron transfer; and reduced integrity and stability of Complex I. Text annotations explicitly list these three deleterious physiological effects, emphasizing the role of SCs in maintaining efficient oxidative phosphorylation and cellular energy metabolism.

This pathophysiology diagram illustrates the role of mitochondrial function and Coenzyme Q10 (CoQ10) in oocyte development and quality. The visual is divided into a macro-scale pathway and a magnified biochemical view of the inner mitochondrial membrane. The magnified section details the Electron Transport Chain (ETC), showing Complexes I, II, III, and IV, alongside CoQ10 and Cytochrome c. It depicts the conversion of NADH to NAD+ and FADH2 to FAD, the pumping of protons (H+) into the intermembrane space, and the reduction of oxygen to water at Complex IV. ATP synthase is shown utilizing the proton gradient to produce ATP from ADP. The larger diagram links these processes to oocyte health: the production of ATP is depicted as a positive driver for embryonic progression from a zygote to a blastocyst. Conversely, the diagram shows Reactive Oxygen Species (ROS) as a byproduct of the Citric Acid Cycle that causes oxidative damage (indicated by a lightning bolt). CoQ10 is highlighted as a critical regulatory component that both facilitates the ETC and inhibits ROS production, thereby promoting optimal oocyte maturity and developmental potential.

A pathophysiology diagram illustrating the mitochondrial oxidative phosphorylation (OXPHOS) system and its therapeutic inhibitors. The top schematic shows the inner mitochondrial membrane containing the Electron Transport Chain (ETC) complexes I through IV, Coenzyme Q (CoQ), and Cytochrome c (Cyt c), alongside ATP synthase (Complex V). It depicts the flow of electrons (2e-) from NADH and FADH2, the pumping of protons (H+) into the intermembrane space, and the final reduction of oxygen to water. Complex V is shown utilizing the proton gradient to convert ADP to ATP. The lower section identifies two pharmacological strategies for ATP depletion in cancer cells: 'Targeting OXPHOS complexes' using drugs like Pyrvinium pamoate, Atovaquone, Niclosamide, and Irinotecan; and 'Targeting Mitochondrial Biogenesis' using antibiotics such as Doxycycline, Tigecycline, and Azithromycin. Inhibitory arrows indicate these drugs disrupt mitochondrial function to target cancer stem cells (CSCs).

This pathophysiology diagram illustrates the role of mitochondrial function and Coenzyme Q10 (CoQ10) in oocyte development and quality. The visual is divided into a macro-scale pathway and a magnified biochemical view of the inner mitochondrial membrane. The magnified section details the Electron Transport Chain (ETC), showing Complexes I, II, III, and IV, alongside CoQ10 and Cytochrome c. It depicts the conversion of NADH to NAD+ and FADH2 to FAD, the pumping of protons (H+) into the intermembrane space, and the reduction of oxygen to water at Complex IV. ATP synthase is shown utilizing the proton gradient to produce ATP from ADP. The larger diagram links these processes to oocyte health: the production of ATP is depicted as a positive driver for embryonic progression from a zygote to a blastocyst. Conversely, the diagram shows Reactive Oxygen Species (ROS) as a byproduct of the Citric Acid Cycle that causes oxidative damage (indicated by a lightning bolt). CoQ10 is highlighted as a critical regulatory component that both facilitates the ETC and inhibits ROS production, thereby promoting optimal oocyte maturity and developmental potential.

A two-part medical illustration depicting mitochondrial oxidative phosphorylation and the broader landscape of reactive oxygen species (ROS) biology. Section (a) shows the electron transport chain (ETC) within the inner mitochondrial membrane, detailing complexes I-IV, ubiquinone (Q), and cytochrome c. It illustrates electron flow from NADH/FADH2 leading to proton pumping into the intermembrane space and ATP synthesis via ATP synthase. The diagram highlights 'leaky' electrons from complexes I and III reacting with O2 to form superoxide (O2•-), which is subsequently neutralized by superoxide dismutase (SOD) and glutathione peroxidase (GPX). Section (b) outlines cellular and external ROS sources, including NADPH oxidase, peroxisomes, radiation, and pathogens. It demonstrates the dual nature of ROS: contributing to pathological oxidative stress (DNA damage, lipid oxidation, protein oxidation) leading to diseases like vascular disorders and neurodegeneration, while simultaneously acting as essential mediators in physiological redox signaling for cell growth, proliferation, apoptosis, and differentiation.