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![Cellular Level
• Unsaturated lipid molecules
of cell membranes are
particularly susceptible to
damage.
• Free radicals breakdown of
lipids resulting in the
hardening of cell wall.
• This can lead to a decrease
intracellular [Ca2+] which
results in reduced neural
activity.](https://image.slidesharecdn.com/freeradicals-240328035151-b6ceb0f8/85/Free-Radicals-CHEMISTRY-presentation-ppt-31-320.jpg)
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Free Radicals CHEMISTRY presentation ppt
- 1. Free Radicals Presented byKendra, Dave, Natalia, Karl, Aneesh, Leif, Kevin, Shivani, Fifi, Sandra and Carolyn
- 2. Free Radicals 1. Whatis a Free Radical 2. How are they created 3. Sources 4. Damage 5. Prevention
- 3. • An atomor molecule with an unpaired electron • Creates an unstable and reactive molecule that will steal an electron from another molecule. What is a Free Radical?
- 4. What is aFree Radical? • This molecule now becomes a new free radical and causes a chain of reactions. • If this occurs inside an organism, it can lead to significant damage.
- 5. How are Freeradicals created? 1. Reduction Loss of an electron 2. Oxidation Gain of an electron 3. Homolytic cleavage The splitting of a complex molecule, into simpler molecules
- 6. 1. Endogenous sources –free radicals produced within the body as normal byproducts of metabolism. 2. Exogenous sources – externally derived sources of free radicals Sources of Free Radical
- 7. 1. Endogenous sources –free radicals produced within the body as normal by products of metabolism. 2. Exogenous sources – externally derived sources of free radicals Sources of Free Radical
- 8. Endogenous sources • Aerobicorganisms use oxygen metabolism because of its ability to yield a high efficiency of energy output. • This causes production of free radicals to occur within all aerobic cells.
- 9. Superoxides • An oxygenmolecule that has gained an electron to become highly reactive 02 -
- 10. 1. Electron transportchain 2. Auto-oxidation 3. Enzymes 4. Heme proteins Superoxides Sources
- 11. • The mostimportant source of O2 - in vivo aerobic cells • Found in the mitochondria and endoplasmic reticulum in eukaryotic cells Superoxides Electron Transport Chain
- 12. • Complexes donate electronsto other complexes down the transport chain. • At times a few electrons leak from the chain directly on to O2 generating O2 -. • Rate of this electron leakage increases with elevated O2 concentration. Superoxides Electron Transport Chain
- 13. • Glyceraldehyde • FADH2 •Hormones adrenalin and noradrenalin • Neurotransmitter dopamine • Thiol compounds, such as cysteine Note: O2 is poorly reactive, so most auto-oxidation reactions are greatly accelerated by transition metals, such as iron and copper. • Several biologically important molecules oxidize in the presence of O2 to yield O2 -. Superoxides Auto-oxidation reactions
- 14. • Intestine and Ischaemictissues • Catalyzes oxidation of both hypoxanthine and xanthine to uric acid while reducing O2 to both O2 - and H2O2. Xanthine oxidase Aldehyde oxidase Nitric oxide synthase Indoleamine 2,3-dioxygenase Tryptophan dioxygenase Superoxides Enzymes
- 15. • Produced inthe Liver • Oxidizes a wide range of aldehydes and other compounds while producing O2 - Superoxides Enzymes Xanthine oxidase Aldehyde oxidase Nitric oxide synthase Indoleamine 2,3-dioxygenase Tryptophan dioxygenase
- 16. • Molecules of oxyhaemoglobin undergodecomposition and release O2 -. • About 3% of the haemoglobin present in human erythrocytes undergo this type of oxidation every day. Superoxides Heme proteins
- 17. Respiratory Burst •Macrophages phagocytoseforeign particles and expose them to enzymatically produced free radicals - O2 -, HOCl, H2O2, OH, NO •The production of these toxic molecules breakdown the foreign particles in the phagosome •Increased cellular O2 consumption is needed to produce them
- 18. 1. Endogenous sources –free radicals produced within the body as normal byproducts of metabolism. 2. Exogenous sources – externally derived sources Sources of Free Radical
- 19. Exogenous Sources • Pollution •Radiation • Cigarettes • Herbicides • On Campus
- 20. Exogenous Sources Air pollution canhave a serious effect on the health of organisms. 0 = N = 0 Nitrogen oxide converted to Nitrogen dioxide Nitrogen dioxide absorbs solar ultraviolet light producing highly reactive ozone which causes lipid peroxidation.
- 21. Exogenous Sources Radiation •X Rays •GammaRadiation •UV Rays Exposure of cells to X-rays can lead to OH- (hydroxyl) production from H2O within the cells. Radioactivity physically disrupts electrons and forms a free radical.
- 22.
- 23. Effects of smoking •In addition to lung cancers, cigarettes can also lead to throat and mouth cancers.
- 24. Exogenous Sources Herbicides • Forexample, paraquat produce free radicals in the form of H2O2 which causes lipid peroxidation to membranes of the lungs.
- 25. Exogenous Sources On Campus •Alcohol has also been shown to be an external source of free radicals.
- 26. Exogenous Sources Photocopiers produce significant amountsof ozone which will peroxidize the lipid membranes of your lungs! How sad! Death by Free Radical.
- 27. Damage • At restour antioxidant defense system can handle free radicals that are produced endogenously. • When rate of free radical production/encounter exceeds the removal rate, damage occurs. • Unpaired electrons are not an energetically favorable or stable state for a molecule.
- 28. Damage • Free Radicalstry to return to a state of stability by taking an electron from some other molecule and restoring its own balance. • This theft causes the damage as the stolen electron may be from a molecule in a normal healthy cell. • Healthy cells are damaged and the body's proper functioning is impaired.
- 29. Damage • Molecular • Cellular •Diseases
- 30. Molecular Level • Directlyattacks DNA and RNA bases • Mitochondrial DNA is the most likely target for free radical attack • As a result, DNA damage and mutation accumulates and interrupts the function of cells causing cell death.
- 31. Cellular Level • Unsaturatedlipid molecules of cell membranes are particularly susceptible to damage. • Free radicals breakdown of lipids resulting in the hardening of cell wall. • This can lead to a decrease intracellular [Ca2+] which results in reduced neural activity.
- 32. • Lipid peroxidationcan be defined as the oxidative deterioration of lipids containing any number of carbon-carbon double bonds. • Free radicals “steal” electrons from the lipids in cell membranes, resulting in cell damage and increased production of free radicals. Example of Damage
- 33. Diseases • Cancer • Alcohol-inducedliver damage • Emphysema • Aging • Heart Disease • Alzheimer’s Disease • Parkinson’s Disease
- 34. Reducing Free Radicals 1.Reduce the exposure to exogenous free radical sources. Antioxidants & Exercise 2. Enhance the bodies own defense systems with…
- 35. 1. Enzymatic 2. Molecular •The body has several antioxidant systems to deal with free radicals. • These are of two types… Antioxidants
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- 37. Superoxide Dimutase Catalase Glatathione Peroxidase Enzymatic Antioxidants • Converts highly reactivesuperoxide into Hydrogen peroxide. • Uses zinc and manganese as co- factors
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- 39. Superoxide Dimutase Catalase Glatathione Peroxidase Enzymatic Antioxidants • Converts highly reactivelipid peroxides into less reactive molecules
- 40.
- 41. Antioxidants Vitamins Carotenoids Bioflavinoids Minerals Molecular Vitamin C • Watersoluble antioxidant Vitamin E •Fat soluble and Transported in LDL cholesterol
- 42. Antioxidants Vitamins Carotenoids Bioflavinoids Minerals Molecular Group of 500+ pigments • Found in plants •Beta-carotene •Leutin •Lycopene
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- 45. Antioxidants Vitamins Carotenoids Bioflavinoids Minerals Molecular In addition. There areother nutrients and compounds that have antioxidant properties, for example… • Coenzyme Q10 • Uric acid
- 46. • Exercise willgreatly enhance the bodies own antioxidant defense system. • Antioxidant enzymes production is increased with exercise, this will counteract the free radicals formed. Antioxidants
- 47. Antioxidants How do antioxidants work? •By “mopping up” the free radicals • The antioxidants neutralize the electrical charge preventing electron theft from the cell.
- 48. Summary • Unpaired electronscause damage at the cellular & molecular level • Endogenous & exogenous sources • Health risks including cancer • Impact may be minimized through decreasing exposure, exercising, eating vegetables, and taking vitamins
- 49. Questions Did free radicalsdo them in?