Free Radicals

What are free radicals?

Atoms or molecules with one or more unpaired electrons in their outer orbital that can exist independently.

What is oxidation?

The gain of oxygen, loss of hydrogen, or loss of electrons.

What are Reactive Oxygen Species (ROS)?

Highly reactive products of partial reduction of oxygen.

How is the superoxide anion radical produced?

By enzymatic processes, autooxidation reactions, and electron transfer to molecular oxygen.

What role do antioxidants play in the body?

Antioxidants neutralize free radicals and protect the body from oxidative stress.

What is the Fenton reaction?

A reaction where hydrogen peroxide reacts with metal ions to produce hydroxyl radicals.

What are the effects of hydroxyl radicals (·OH) on cells?

They can strongly react with organic and inorganic molecules, causing severe cellular damage.

What initiates lipid peroxidation?

The formation of lipid peroxy radicals by free radicals.

What are the endogenous sources of ROS?

Sources such as mitochondria, peroxisomes, and the endoplasmic reticulum where oxygen consumption is high.

What is oxidative stress?

A condition resulting from the imbalance between free radicals and antioxidants, leading to potential damage to biological molecules.

What are the harmful effects of excessive free radicals on carbohydrates?

They can lead to chain breaks in molecules like hyaluronic acid, affecting joint fluid.

What consequence can DNA damage from free radicals lead to?

Mutations, which can form the basis for cancer and other diseases.

What is the role of nitric oxide (NO•) in the body?

It is a signaling molecule that helps in smooth muscle relaxation, blood pressure regulation, and immune response.

What does lipid peroxidation negatively affect?

Cell membrane integrity, leading to altered fluidity and signaling disruptions.

Which enzymes are involved in the defense against oxidative stress?

Enzymatic systems such as Catalase (CAT), Superoxide Dismutase (SOD), and Glutathione Peroxidase (GSH-PX).

Oxidative stress occurs when there is an imbalance between free radicals and __________.

antioxidants.

The process of __________ involves the addition of oxygen to a substance.

oxidation.

Hydroxyl radicals can cause significant damage to __________ molecules.

cellular.

A common method for detecting oxidative stress is measuring the levels of __________ products.

lipid peroxidation.

Superoxide dismutase (SOD) is an important __________ that addresses oxidative damage in the body.

enzyme.

Free radicals can initiate lipid peroxidation by forming lipid __________ radicals.

peroxy.

Reactive oxygen species (ROS) can be produced from normal __________ functions.

metabolic.

Excessive free radicals can lead to DNA __________, which may result in cancer.

damage.

Antioxidants are compounds that can donate electrons to stabilize free __________.

radicals.

The Fenton reaction ultimately produces hydroxyl __________ from hydrogen peroxide and metal ions.

radicals.

What is a free radical?

A free radical is an atom or molecule with one or more unpaired electrons in its outer orbital.

What is the primary role of antioxidants?

Antioxidants neutralize free radicals to prevent oxidative damage.

How does oxidative stress affect health?

Oxidative stress can lead to cellular damage, contributing to diseases like cancer and neurodegenerative disorders.

What is the significance of superoxide dismutase (SOD)?

SOD is an enzyme that helps break down superoxide radicals into less harmful molecules.

What are the sources of Reactive Oxygen Species (ROS) in the body?

Endogenous sources include mitochondria, peroxisomes, and the endoplasmic reticulum.

What type of damage can hydroxyl radicals cause?

Hydroxyl radicals can cause significant damage to proteins, lipids, and nucleic acids.

What is lipid peroxidation?

Lipid peroxidation is the oxidative degradation of lipids, leading to cell membrane damage.

What role does nitric oxide (NO•) play in the body?

Nitric oxide acts as a signaling molecule, involved in processes like vasodilation.

What is the result of excessive free radical activity?

Excessive free radicals can disrupt cellular function and lead to various diseases.

How do free radicals initiate chain reactions in cells?

Free radicals can abstract electrons from stable molecules, causing them to become free radicals themselves.