Topic 9 - Free Radicals and Antioxidants

____________ boots the activity of cancer-destroying enzymes and prevent gut bacteria from converting nitrates to nitrites.

Alliums

_____________ has biological activity; Vitamin E activity.

Alpha-tocopherol

_______ ________ supplementation can reduce lipid preoccupation and can protect LDL.

Beta carotene

Vitamin ____ is required to maintain Fe and Cu in ______________________ in a reduced state.

C, metalloenzymes

True or False: Hydrogen peroxide is a radical.

False; hydrogen peroxide is not a radical but is a reactive oxygen species

______________ are the largest category pf phytochemical (anthocyanin and anthoxanthins): bound to _______________.

Flavonoids, glycosides

__________ _______ are normal by-products of aerobic metabolism (ETC)

Free radicals

______________ are atoms, molecules or ions that have one or more unpaired electrons

Free radicals

In platelets ______ acts as anti-aggregating factor; reduces fat peroxide formation and increases the ratio of prostacyclin thromboxane.

GPX

GSSG -----(___________)---> 2 GSH NADPH + H+ ---> NADPH Uses NADPH generated from the hexosemonophosphate shunt

Glutathione reductase

_____________ is the most effective quencher and is found in tomatoes.

Lycopene

Vitamin C can be regenerated with?

Niacin as NADH Dihydrolipoic acid Glutathione Thioredoxin

____________ is required to break up aromatic amino acids.

Oxygen

______________/Carotenoids are capable of quenching ________ molecular oxygens and other free radicals.

Vitamin A

Hydroxylation of phenylalanine requires _________ __.

Vitamin C

Regeneration of Vitamin E involves?

Vitamin C Glutathione NADPH

Regeneration of Vitamin E involves _________ _____, ____________ and ____________.

Vitamin C, glutathione, NADPH

Phytochemicals are found in diets rich in _______ and _________.

fruits, vegetables

Hydroxyl radical is also generated through exposure to ______________ rays and low wavelength ______________ ___________.

gamma, electromagnetic radiation

Ascorbic acid is regenerated by _______________.

gultathione

Free radicals have _________ reactivity

high

Hydroxyl radicals are generated from ______________ _____________.

hydrogen peroxide

Superoxide radical is the initiator of chain reactions leading to other reactive species such as ___________ ___________ and ____________.

hydrogen peroxide, hydroperoxyl

GPX catalyzes the removal of ________ ________ and _________ from tissues.

hydrogen peroxides, hydroperoxides

Vitamin E has a phenolic ring that donates ___________ ions to radicals. Vitamin E gets ________ in the process.

hydrogen, oxydized

Vitamin C is water soluble, making it ___________.

hydrophilic

Vitamin C reacts with __________ radial to produce water and unreactive _____________________ radical.

hydroxyl, semihydroascorbate

Glutathione cycles between an ________ form (GSSH) and a _________ form (GSH)

oxidized, reduced

Hydroxyl radical is a _________ centered radical.

oxygen

Superoxide radical is a ___________ centered radical.

oxygen

Vitamin C can provide electrons to reduce the ___________ radical to form _________ __________ and ___________.

superoxide, hydrogen peroxide, DHAA

Hydrogen peroxide reacts with __________ to form _________ radical (highly reactive)

superoxide, hydroxyl

The oxidized form of superoxide dismutase reacts with one ________ ion to form _________ and generates the reduced form of the enzyme.

superoxide, oxygen

Tocotrienols have ______________ side chains.

unsaturated

Hydrogen peroxide easily diffuses in ________ and _______ to cause damage.

water, lipids

Extracellular and cytosolic superoxide dismutase requires _________ and ___________.

zinc, copper

GSH:GSSH ratio in cells is indicator of redox state usually _________.

>10

____________ are yellow-orange pigments found in plants.

Carotenoids

____________ of tyrosine requires __________ __.

Catabolism, Vitamin C

____________ is a triple helix made up of three extended protein chains wrapped around each other.

Collagen

Vitamin ____ prevents/terminates the ___________ reaction.

E, propagation

________ are essential for various defense mechanisms in most cells

ROS

True or False: Hydrogen peroxide can move away from the site of origin.

True

True or False: Hydroxyl radical can exist in the membrane and damage the membrane.

True

True or False: Hydroxyl radical is the most potent reactive radical.

True

True or False: Lutein and zeaxanthin are carotenoids that are good for eye health (macula)

True

True or False: Superoxide radical does not diffuse too far away from source of origin.

True

True or False: Superoxide radical forms easily in the ETC and mitochondria.

True

True or False: Tocopheroxy radical must be reduced.

True

True or False: Vitamin E is most effective in dealing with peroxy radicals.

True

True or False: SOD works faster than Vitamin C.

True

True or False: Free radicals and other reactive oxygen species (ROS) are formed during normal cellular metabolism

True

True or False: GPX is important in phagocytic cells like macrophages (oxidative destruction)

True

True or False: Vitamin A/carotenoids require no enzymes, thus does not require regeneration.

True

Hydrogen peroxide is also generated during reactions involving __________ - elimination of superoxide.

ascorbate

Vitamin C forms as ____________ acid.

ascorbic

Major role for selenium is as a __________ of ___________ such as Glutathione peroxidase (GPX).

co-factor, enzymes

Vitamin C is required or reactions in ___________ synthesis, canitine synthesis, tyrosine synthesis, and ____________ synthesis.

collagen, neurotrasnmitter

Glutathione is a tripeptide that consists of _________ residue flanked by a ___________ residue and a _________ residue.

cysteine, glutamate, glycine

Glutathione is synthesized by most cells and is found in the __________ and also in __________.

cytosol, plasma

Ascorbate can donate _________ and _________ ions to quench electrons.

electrons, hydrogen

Indoles inactivate ___________.

estrogen

Photoreceptors are found in the __________.

eyes

Glutathione has the ability to scavenge ________ _________ (O2 and OH)

free radicals

When the lipid peroxyl radical goes under a propagation reaction it makes a __________ _________.

lipid peroxide

Singlet oxygen is generated from _________ peroxidation, __________ activation or ____________ reaction.

lipid, neutrophil, photochemical

A __________ radical in the presence of oxygen creates a lipid ___________ radical.

lipid, peroxyl

Membranes of tissues such as __________, __________, and __________ have a higher degree of unsaturation, metabolism and oxygen presence.

lungs, RBCs, brain

Mitochondrial superoxide disputes requires _________.

manganese

Free radicals are generated by ________ reactions and also through _________ exposure

metabolic, environmental

Glutathione reductase is not a __________ enzyme.

metal

Metabolism of selenium is related to its role in sulfur containing amino acids _________ and __________.

methionine, cysteine

Hydroxyl radical is a major initiator of lipid _____________; reacts with __________ _________, and proteins.

peroxidation, nucleic acids

Other reactions that generate hydrogen peroxide includes _________, trauma and ____________.

peroxisomes, injury

Beta carotene is effective in reacting with _________ radicals and works synergistically with Vitamin ______.

peroxyl, E

Tyrosine is synthesized from ______________.

phenylalanine

Isoflavones and lignin are ____________, found in soybeans, flaxseeds and barley.

phytoestrogen

The reduced form of SOD reacts with another superoxide ion and two _________ to form __________ __________ and regenerates the oxidized form of the enzyme.

protons, hydrogen peroxide

Free radicals that contain oxygen are called _____ ________ species

reactive oxygen species (ROS)

Superoxide radicals are generated during reactions involving __________ of ___________ substances like bacteria and viruses in activated white blood cells (respiratory burst).

removal, foreign

Tocopherols have _____________ side chains.

saturated

Glutathione peroxidase (GPX) is ___________ dependent

selenium

Glutathione contains a ____________ group in its reduced form (GSH).

sulfhydryl

Indoles and alliums are _____________ containing phytochemical.

sulfur

Hydrogen peroxide is generated through the action of ___________ ____________.

superoxide dismutase