Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of oxidative stress, a state often resulting from exposure to high levels of reactive oxygen species, e.g. superoxide anions, hydrogen peroxide (H2O2), and hydroxyl radicals.

The process of restoring a protein to its original state after damage by such things as oxidation or spontaneous decomposition of residues.

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.