Oxygen Toxicity

Question 0

______ is probably the most potent ROS

Answer 0

Hydroxy radical

Question 1

When O2 accepts single electrons, it is transformed into highly reactive ________ that demage cellular lipids, proteins and DNA

Answer 1

Oxygen radicals

Question 2

One oxygen molecule can accept up to ______ electrons, generating __________

Answer 2

4
Superoxide, hydrogen peroxide
Hydroxyl radical, water

Question 3

Hydrogen peroxide is not a radical but a ______ because it can generate hydroxyl radical

Answer 3

ROS

Question 4

Transition metals, such as Fe2+ or Cu+, catalyze formation of the _______ from _____ in he non-enzymatic Fenton reaction

Answer 4

hydroxyl radicals

hydrogen peroxide

Question 5

under physiological conditions, ____ are sequestered to reduce Fenton reaction. However, _____ can expose such metals to allow secondary free radical injury

Answer 5

transition metals

Injury

Question 6

RNOS contain both nitrogen and oxygen and derive principally from the free radical ________

Answer 6

Nitric oxide (NO)

Question 7

Free radical nitric oxide is produced endogenously by enzyme _______

Answer 7

Nitric oxide synthase (NOS)

Question 8

One of the major sites of superoxide generation is ________ in the mitochondria electron transport chain

Answer 8

Coenzyme Q (CoQ)

Question 9

The _______ form of CoQ can accidentally transfer an electron to dissolved O2, thereby forming _______

Answer 9

One-electron reduced

Superoxide

Question 10

Name 3 enzyme in the cell that bind O2 and transfer single electron to it via a metal

Answer 10

Oxidase
Peroxidase
Oxygenase

Question 11

_______ enzymes are a major source of free radical leakage

Answer 11

Cytochrome P450

Question 12

Induction of cytochrome P450 enzyme by ____, ____ or ____ leads to increased cellular injury

Answer 12

Alcohol
Drug
Chemical toxicant

Question 13

_____ and _____ are generated enzymatically as major reaction products by several oxidase present in peroxisome

Answer 13

Hydrogen peroxide

Lipid peroxide

Question 14

Peroxisomal ________ generates hydrogen peroxide

Answer 14

Fatty acyl-CoA oxidase

Question 15

Lipid peroxidase are formed enzymatically as intermediate in the pathway of many ______, including leukotrienes and prostaglandin

Answer 15

Eicosanoids

Question 16

Ionizing radiation has a high energy level that it can split water into ___ and ____.

Answer 16

Hydroxyl

Hydrogen radical

Question 17

Ionizing radiation can generate organic radical through direct collision with ______

Answer 17

Organic cellular component

Question 18

______ that form lipid peroxyl radical and lipid peroxide make a major contribution to ____ -induced injury

Answer 18

Chain reaction

ROS

Question 19

Initiator free radical, such as _______, begins chain reaction by extract a hydrogen atom from the double bond of _______ in membrane lipids

Answer 19

Hydroxyl radical

Polyunsaturated fatty acid

Question 20

After extraction of hydrogen atom from fatty acid, the chain reaction is propagated when ______ adds to form _____ and _____.

Answer 20

O2
Lipid peroxyl radial
Lipid peroxide

Question 21

Disruption of membrane integrity of membrane attack may result in further ______

Answer 21

Free radical production

Question 22

_____ of lipid molecules can cause lipid degradation

Answer 22

Peroxidation

Question 23

_____ formed from lipid peroxidation can _____ proteins

Answer 23

Aldehyde

Cross-link

Question 24

As a result of oxidative damage, protein may cause _______, _____ and ______

Answer 24

Fragmentation Crosslinking Aggregation

Question 25

Oxidation of cysteine sulfhydryl group of _______ compromise the cellular defense against free radical injury.

Answer 25

Glutathione

Question 26

Oxygen derived free radical can cause ______ in DNA and also cause ______ backbone breakage

Answer 26

Base alteration | Deoxyribose

Question 27

Nitric Oxide (NO) has a single electron and hence is ______

Answer 27

Free radical

Question 28

At a low concentration, NO function as a ______ and as a hormone causing ______

Answer 28

Neurotransmitter | Vasodilation

Question 29

At high concentration, NO combines with _____ or with _____ to form RNOS

Answer 29

O2 superoxide

Question 30

RNOS is involved in neurodegenerative disease such as _______ and in chronic inflammation such as _____

Answer 30

Parkinson's disease | Rheumatoid arthritis

Question 31

NO is synthesized by the enzyme _______ from argnine

Answer 31

NO synthase

Question 32

NOS has 3 tissue specific Isoform

Answer 32

Neuronal Endothelial Inducible

Question 33

Neuronal and endothelial NOS are tightly regulated by ____ concentration and generate NO that serve as _____ or ______

Answer 33

Calcium Neurotransmitter Hormone

Question 34

Inducible NOS are present in many cells of the immune system and can be induced to high level of expression and generate ______

Answer 34

RNOS

Question 35

NO exert direct toxicity by attack ______ of ETC and Fe-heme protein such as Hb and cytochromes

Answer 35

Fe-S center

Question 36

Under physiological condition, the effect caused by direct NO toxicity is low due to low abundance of ____

Answer 36

NO

Question 37

Direct NO toxicity can cause serious damage in individual with _____ or ischemia

Answer 37

Oxidative phosphorylation disease

Question 38

Superoxide dismutase converts _____ to _______

Answer 38

Superoxide | Hydrogen peroxide

Question 39

In response to infectious agents and other stimuli, phagocytic cells of the immune system exhibit a rapid consumption of O2, in a process called _______

Answer 39

Respiratory burst

Question 40

Respiratory burst is a major source of _______ (5 )

Answer 40

``` Superoxide Hydrogen peroxide Hydroxyl radical HOCl RNOS ```

Question 41

Generation of free radical during _______ is intended to destroy invading microorganism or tumor cell.

Answer 41

Respiratory

Question 42

The respiratory burst results from the activity of _______, which catalyze the transfer of an electron from NADPH to O2 to form ______

Answer 42

NADPH oxidase | Superoxide

Question 43

Myeloperoxidase converts ______ to _______

Answer 43

H2O2 | HOCl

Question 44

formation of hypochlorous acid from hydrogen peroxide is catalyzes by ________, a heme containing enzyme that is present only in phagocytic cell

Answer 44

Myeloperoxidase

Question 45

Peroxisomal fatty acyl-coa oxidase generates _______

Answer 45

hydrogen peroxide

Question 46

2 examples of endogenous free radical scavengers are _____

Answer 46

Uric acid | Melatonin

Question 47

Name 4 dietary free radical scavenger

Answer 47

Vitamin C Vitamin E Carotenoids Flavonoids

Question 48

Vitamin E is ____ soluble and protect the membrane against _____

Answer 48

Lipid | Lipid peroxidation

Question 49

Reduced vitamin c can regenerated the ____ form of ____ by donating electron

Answer 49

Reduced | Vitamin E