What is a free radical characterized by?

A free radical is characterized by having one or more unpaired electrons in its outer shell.

During normal oxidative reactions, oxygen is fully reduced to ______.

Water

True or False: Hydrogen peroxide (H₂O₂) is considered a free radical.

False. Hydrogen peroxide is a reactive oxygen species but does not have an unpaired electron.

Which radical is considered the most potent oxygen free radical?

Hydroxyl radical (•OH)

Riddle: I form when an electron is transferred to oxygen, creating both a radical and an anion. What am I?

Superoxide radical (•O₂⁻)

The Fenton Reaction involves the transfer of an electron from ______ to hydrogen peroxide.

Ferrous ion (Fe²⁺)

Which enzyme is primarily responsible for producing superoxide during the respiratory burst?

NADPH oxidase

Fill in the blank: Lipid peroxidation primarily damages ______ in cell membranes.

Polyunsaturated fatty acids (PUFAs)

True or False: Free radicals exist for long periods before reacting with other molecules.

False. Free radicals exist for a very short time (about 10⁻⁹ to 10⁻¹² seconds).

What is the primary method to neutralize a free radical?

When two free radicals react together, allowing their unpaired electrons to pair up.

Which assay is used to measure lipid peroxides in biological samples?

FOX (Ferrous Oxidation in Xylenol) Assay

Which antioxidant is crucial for converting hydrogen peroxide into water and oxygen?

Catalase

Riddle: I help protect cells from oxidative damage but can act as a prooxidant under certain conditions. What am I?

Ascorbate (Vitamin C)

Fill in the blank: The hydroxylation reaction in Phase 1 metabolism is primarily carried out by ______.

Cytochrome P450 enzymes

Which phase in xenobiotic metabolism involves conjugation with glucuronic acid?

Phase 2

True or False: The primary metabolic pathway for ethanol is through the action of aldehyde dehydrogenase.

False. Ethanol is primarily metabolized by alcohol dehydrogenase.

What is the outcome of increased NADH levels after alcohol consumption?

It leads to a high NADH/NAD⁺ ratio, resulting in lactic acidosis.

Which antioxidant is known for preventing lipid peroxidation and is a fat-soluble vitamin?

Vitamin E (α-Tocopherol)

Riddle: I am a molecule that helps detoxify harmful substances but can also be a source of toxic effects when present in excess. What am I?

Acetaldehyde

Fill in the blank: The enzyme responsible for converting ethanol to acetaldehyde is ______.

NAD⁺ dependent cytoplasmic alcohol dehydrogenase

What are the two types of superoxide dismutase (SOD) based on their metal requirements?

Cytosolic SOD (Cu-SOD) and Mitochondrial SOD (Mn-SOD)

True or False: Cytochrome P450 enzymes are found only in the liver.

False. They are present in nearly all tissues, including the liver and enterocytes.

Which compound is produced when lipid peroxides further break down?

Reactive dialdehydes

Fill in the blank: The acetyl donor in acetylation reactions is ______.

Acetyl-CoA

What metabolic pathway is primarily responsible for the formation of ketone bodies?

Ketogenesis, triggered by the accumulation of Acetyl CoA.

Riddle: I help scavenge free radicals and am a natural antioxidant in the body. What am I?

Uric Acid

Which reaction is involved in the metabolism of xenobiotics and can activate them to active forms?

Phase 1 reactions

What is the primary role of glutathione peroxidase in the body?

To eliminate harmful substances like hydrogen peroxide.

Fill in the blank: The process by which benzoic acid is conjugated to form hippuric acid is known as ______.

Conjugation with glycine

True or False: All reactive oxygen species (ROS) have unpaired electrons.

False. Hydrogen peroxide is a ROS but does not have unpaired electrons.