<prompt> Lipid peroxidation as a cause of ageing and injury of cell is:2001Free radical theoryApoptosis theoryEnzyme cascade theoryCell destruction theory  <response>: Ans: a Free radical theoryRef: Robbins, 7th ed, p. 125 6th ed, p. 48Free radicals produced during injury or aging cause oxidative decomposition of the lipid. Due to oxidative decomposition organic peroxides are formed after reacting with oxygen lipid peroxidation.This reaction is auto-catalytic i.e., new radicals are formed from the peroxide radicals themselves. These radicals cause structural and functional breakdown of endoplasmic reticulum. 