65091
Description
Flashcards by alexlpeart, updated more than 1 year ago
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Created by alexlpeart
over 12 years ago
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| Question | Answer |
| What is oxidative stress? | The imbalance between pro-oxidants and anti-oxidants. |
| What are free radicals? What are Reactive oxygen species? | Free radicals have one unpaired electron (indicated by a dot) where as reactive oxygen species must contain an oxygen molecule as well as having unpaired electrons. |
| Give 3 examples of reactive oxygen species. | Hydrogen peroxide, Ozone and Hypochlorous acid. |
| Give some positives of ROS and RNS at moderate intensities of exercise. | They cause adaption meaning we have better antioxidant enzyme capacity in our cells. They also increase exercise enzymes which increases vasodilation and blood flow. |
| What intensity exercise does oxidative stress become a problem. Why does it become a problem? | Very intense exercise. It causes increased protein oxidation damaging the structure and function of the protein, increases lipid oxidation (athrogenic) and increases DNA oxidation (cell death). |
| Give methods of measuring oxidative stress. Use both real time measures and indirect measures. | Real time - Electron spin tapering, Molecular probes, Micro-dialysis (sticking things like aspirin in and seeing how oxidized they get), Immune cell isolation (centrifuge to separate cells, use lasers to determine cell type, is certain immune cells low oxidative stress must be high). Indirect measures - Oxidative stress markers (molecules with oxidative damage found in the body), Use a know oxidant and see plasma's ability to counteract it. |
| How can RONS (reactive oxygen or nitrogen species) be formed at rest of very low intensity exercise? | Oxidative phosphorylation in the mitochondria causes electron leak and generate RONS. |
| Describe the process which causes ROS to be formed during high intensity exercise. | Under normal conditions with normal/high oxygen, Purines are broken down into uric acid by xanthine dehydrogenase and the electrons released are transferred onto NADH. When we experience low oxygen in the tissue such as very hard training or during a stroke xanthine dehydrogenase is converted to xanthine oxidase. This still converts purines into uric acid however the electrons are now transferred onto oxygen creating O2- which can form O3 which is a reactive oxygen species (ozone) |
| Describe how exercise dose affects oxidative stress. | No exercise is bad as we don't get any adaption to oxidative stress. Low-moderate intensity is good as it causes adaption increasing antioxidant capacity. High intensity may cause damage to our cells. |
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