Progressive (exponential) Elderly patients have ragged red fibers accumulating Elderly patients accumulate mtDNA damage So how do these `symptoms” of aging happen? What are free radicals? Where do they come from? What damage do they do? What are the effects of this damage? What can we do? What are oxygen free radicals? Free radicals are when oxygen has an unpaired electron What damage can they do? Primarily they can react with deoxyribose and DNA bases Where do they come from? These free radicals result from the `dumping” of electrons from the ETC onto free oxygen Remember this? What is the evidence that this helps cause aging?