Oxidative Stress Mind Map PDF

Restores ATP but generates additional ROS **Definition:** Imbalance between ROS (ischemia-reperfusion injury)....

Restores ATP but generates additional ROS **Definition:** Imbalance between ROS (ischemia-reperfusion injury). production and antioxidant defenses, leading to **Reoxygenation:** Treatment of Ischemia damage to proteins, lipids, nucleic acids, and **Antioxidants:** Administered during reperfusion cellular structures. to reduce oxidative damage. Oxidative Stress **Importance:** Central to aging, cancer, cardiovascular diseases, and other pathologies. ROS damage endothelium, increasing permeability to lipoproteins. **Mechanism:** Essential for ATP production as the terminal Oxidized lipoproteins form plaques, triggering electron acceptor in the mitochondrial ETC. inflammation. O₂ and Its Metabolic Importance **O₂'s Role:** ROS and Atherosclerosis Reactivity leads to ROS formation, which can **Ischemia:** Obstruction of blood flow leads to cause cellular damage. ATP depletion, acidosis, and cell death. **Metabolic Consequences:** **Anaerobic glycolysis:** Increased lactate production, low pH. 5% of O₂ undergoes univalent reduction forming ROS. reactive oxygen species (ROS) **Superoxide anion (O₂⁻·):** Initial ROS formed. Calorie restriction reduces metabolic rate, lowering ROS production. **Hydrogen peroxide (H₂O₂):** Precursor to **Major ROS:** hydroxyl radicals. Leads to a slower accumulation of oxidative **Hypothesis:** ROS and Calorie Restriction O₂ and ROS Production **ROS Formation:** damage. **Hydroxyl radical (OH·):** Highly reactive and damaging. Observed in multiple organisms, suggesting longer life expectancy. **Mitochondria:** Leakage from ETC complexes. **Peroxisomes:** During β-oxidation of fatty **Sources of ROS:** acids. ROS accumulation reduces cellular function and regeneration. **Enzymatic Reactions:** Oxidases and **Mechanisms:** ROS and Aging oxygenases. Declining antioxidant capacity exacerbates damage. **Superoxide radical (O₂⁻·):** Primary ROS, limited reactivity. 1. **Aging:** Reduced regeneration, increased ROS damage. **Hydrogen peroxide (H₂O₂):** Membrane- 2. **Carcinogenesis:** ROS-induced mutations **Conditions Linked to ROS:** ROS and Associated Physiological Oxidative Stress Mind Reactive Oxygen Species (ROS) **Key ROS Types:** permeable, can form OH·. promote cancer. Changes Map **Hydroxyl radical (OH·):** Most reactive, damages macromolecules. 3. **Atherosclerosis:** ROS damage to endothelial cells leads to plaque formation. **Singlet oxygen (¹O₂):** Produced during photooxidation. **Superoxide dismutase (SOD):** Converts O₂⁻· to H₂O₂. Oxidation of thiol groups in cysteine residues alters function. **Catalase:** Breaks down H₂O₂ to water and **Primary Defenses:** **Protein Damage:** oxygen. Carbonylation signals proteolysis, reducing protein stability. **Glutathione peroxidase (GPx):** Reduces H₂O₂ and lipid hydroperoxides. Antioxidant Defenses Hydroperoxides and aldehydes. **DNA Repair Enzymes:** Fix ROS-induced DNA Toxic Effects of ROS **Lipid Damage:** Lipid peroxidation of PUFAs leads to: damage. Disrupts membrane integrity, fluidity, and signaling. **Secondary Defenses:** **Proteases, Nucleases:** Repair or degrade oxidized molecules. Oxidized guanine (e.g., 8-oxoG) induces mutations and replication errors. **DNA Damage:** Strand breaks, cross-links impair DNA replication Decreases meat and milk quality. and transcription. **Impact on Livestock:** Reduces immune function, increases disease susceptibility. Oxidative Stress in Animals **Xenobiotics:** Chemicals inducing ROS via metabolism (e.g., cytochrome P450). Protects against ROS, improves health and **Role of Dietary Antioxidants:** productivity. **Exogenous Factors:** **Ionizing Radiation:** Splits water to form ROS. **Hyperoxia:** Elevated oxygen concentration Disrupts enzyme function, accelerates overwhelms antioxidant defenses. proteolysis. **Protein Oxidation:** Factors Promoting Oxidative Stress **Mitochondrial Dysfunction:** Increases ROS Uncontrolled, autocatalytic chain reactions form leakage. reactive by-products. **Endogenous Factors:** **Lipid Peroxidation:** **Antioxidant Deficiency:** Aging, nutrient Alters membrane fluidity and disrupts cellular deficits reduce ROS scavenging. signaling. ROS and Oxidative Damage ROS induce oxidative DNA lesions, causing **DNA Damage:** replication errors and mutations. **ATPase inhibition:** Disrupts osmotic balance, ion gradients. **Cellular Consequences:** **Increased [Ca²⁺]:** Activates destructive enzymes (proteases, lipases, nucleases).