Oxidative Balance

Question 1

ROS

Answer 1

reactive oxygen species;

molecular O2, OH-, OH. (radical), superoxide O2-. (1 unpaired and charged)

Question 2

RNS

Answer 2

reactive nitrogen species; nitric oxide NO. (1 unpaired)

Question 3

unstable O-O bonds

Answer 3

H2O2 bonds, ONOO-

Question 4

cell to cell messages via NO

Answer 4

smooth muscle relaxation, vasodilator, neurotrans, hair follicle life cycle;
endothelial cells with NOS release NO and they react with guanylyl cyclase in smooth cells–> vasodilation

Question 5

NO synthase

Answer 5

L-arginine undergoes reaction with NOS (1,2,or 3) and turns into L-CItrulline + NO.
Uses 2 NADPH

Question 6

What inhibits NO

Answer 6

Myoglobin

Question 7

Intracellular ROS

Answer 7

superoxide (made through leaky electrons in the ETC pathway); superoxide dismutase binds the superoxide and binds free radical and makes hydrogen peroxide

Question 8

hypothesis of superoxide

Answer 8

metabolic state of the cell determines superoxide activity; more ETC activity–> more superoxide; the receptor proteins sense change and the transcriptome/proteome responds

Question 9

e- in the process of O2 causes

Answer 9

free radicals

Question 10

enhancing ROS production during ETC

Answer 10

high ETC–> make more ADP, slow down TCA (ADP limiting factor)

Question 11

diminish ROS production during ETC

Answer 11

uncoupling protein transports H+ into inner membrane without making ATP and ETC is low. Adapt needed–> increase CA cycle;

Question 12

ROS in inflammation and immunity

Answer 12

NADPH oxidase and arachidonic acid catabolism

Question 13

NADPH oxidase

Answer 13

in neutorphils;
NADPH redox reaction to NADP which removes e- and reacts with O2 to make superoxide going into phagocytic vesicle or go outside cell;
it’s the first line of defense against infection

Question 14

how is superoxide used against bacteria?

Answer 14

bacteria are rich in unsequestered Fe2+. Superoxide with protons creates H2O2 which then reacts with Fe2+ via fenton reaction to create more HO. + OH-+ Fe3+

free radicals and metals–> snowball affect

Question 15

arachidonic acid catabolism

Answer 15

signaling: inflammation and immunity
messengers: nervous system
direct result of autooxidation;
creates leukotrienes and prostanoid eicosanoids

Question 16

haber-weiss reaction

Answer 16

superoxide and hydrogen peroxide make more hydroxy radical and hydroxy anion and O2 via free iron

Question 17

ROS attack

Answer 17

bases and backbone of nucleic acids, amino acid side chains, double bonds of unsaturated fatty acids;
non specific

Question 18

dityrosine bridges

Answer 18

cross linked protein which cannot be degraded via proteosome; created via cysteine, lysine, proline, arginine, metionine cross links

Question 19

oxidative damage: membrane

Answer 19

via arachidonic acid it creates peroxy cpds, hydroperoxy cpds, OH radical and isoprostanes which lead to rancid membranes

Question 20

PUFA chain reaction

Answer 20

depletes membrane unsaturated fatty acids; diminished fluidity of membrane

Question 21

oxidative damage to macromolecules

Answer 21

DNA mutagenesis, protein loss of function, protein aggregation, impaired protein disposal, loss of membrane fluidity, toxic lipid peroxidation byproducts

Question 22

generalized control of ROS

Answer 22

redundant, enzymatic, nonenzymatic

Question 23

superoxide dismutase

Answer 23

acts on superoxide

Question 24

catalse

Answer 24

acts on hydrogen peroxide

Question 25

glutathione peroxidase/reducase

Answer 25

acts on H2O2;

inactivated by nonspecific glycation in diabetes

Question 26

thioredoxin enzymes

Answer 26

peroxiredoxin/thioredoxin reductase, variety of substrates

Question 27

SOD

Answer 27

superoxide dismutase;

takes two superoxides and combines in to hydrogen peroxide

Question 28

catalase reaction

Answer 28

two hydrogen peroxides to two water and one o2 molecules

Question 29

non enzymatic antioxidants

Answer 29

tend to be reduced at baseline; accept or donate electrons; become radicals during the process but they are less reactive than neutralized radical because of resonance

Question 30

drawbacks of antioxidant use

Answer 30

kidney or liver malfunction changes antioxidant metabolism; may interfere with normal signaling or immune response (NADPH oxidase),

Question 31

why can vitamin c exacerbate kidney stones?

Answer 31

one of the metabolites of vitamin c is oxalate. oxalate is a main component of kidney stones