Reactive Oxygen Species (ROS)

Flashcards about Reactive Oxygen Species (ROS) in Radiation Biology

Reactive Oxygen Species (ROS)

Molecular species that are highly reactive molecules containing Oxygen. Byproducts of normal cellular metabolism, but are significantly increased under oxidative stress.

Oxidation

A chemical process where an atom or molecule loses an electron; Loss of electron, Loss of Hydrogen, Gain of Oxygen.

Reduction

A chemical process where an atom or molecule gains an electron; Gain of electrons, Gain of Hydrogen, Loss of Oxygen.

Oxidants (Oxidizing agents)

Molecules that cause oxidation; they “steal” electrons from other molecules. The molecules that lose electrons are “oxidized”.

Reductant (Reducing agents)

Molecules that donate an electron to another molecule. The molecules that gain electrons are “reduced”.

Free Radicals

An oxidant with an unpaired electron in its outer shell. This unpaired electron makes free radicals highly reactive because they desperately seek another electron to achieve stability.

Non-radical oxidant

An oxidizing molecule that doesn’t have an unpaired electron, but can still participate in redox reactions and generate free radicals.

Radiolysis

The process where ionizing radiation interacts with water molecules, generating ROS.

Solvated electron (e⁻ₐq)

Ejected electrons that are stabilized by water molecules due to the dipole-dipole interaction of water molecules and the electrostatic and hydrostatic interactions of water molecules. Still chemically reactive.

8-oxoguanine

A common oxidative DNA modification caused by ROS attack, leading to mispairing during DNA replication which is repaired by BER by the 8-oxoguanine glycosylase enzyme.

Lipid Peroxidation

The process by which ROS destroy lipids, leading to leaky membranes and cell dysfunction.