Ros

Front 1

Advantages of O2

Back 1

final acceptor in the ETC.
can oxidize other fatty acids and fuel molecules.

Front 2

Disadvantages of O2

Back 2

forms reactive O2 species.

Front 3

Damage done by the O2 radical species

Back 3

depolymerize polysaccarides involved in storage.
deconstruct the membrane by breaking double bonds.
denatures and inactives the enzymes.
damages DNA by disrupting the phosphate backbone.

Front 4

Oxidative Stress

Back 4

the antioxidants are overwhelmed and radicals can not be delt with.

Front 5

4 types of reactive O2 species.

Back 5

1. superoxide radical - precusor, O2 reacts with electron.
2. H2O2 - less reactive of the 4.
forms when O2.- reacts with H+ to form singlet and hydrogen peroxide.
3. Hydroxide radical- very reactive but short lived.
H2O2 reacts with iron. Iron is oxidized to Fe(III).
4. singlet O - very reactive because one electron moves up an orbital and when fall doawn it releases energy.
made same as H2O2 or preoxide goes to alcohol and singlet O2.

Front 6

Ways to generate ROS in body.

Back 6

in ETC - can donate an electron to O2 to generate superoxide radical.
fatty acid desaturation - transfer electron to O2.
uv light
ionization
resiratory bursts- happens in macrophages, used to get rid of bacteria or foreign substance.
In the lysosome NADPH oxidase converts O2 to superoxide radical and oxidizes NADPH.

Front 7

Defenses against Oxidative Stress.

Back 7

convert ROS to something less toxic.
prevent formation of hydroxide radical and singlet.

Front 8

Superoxide Dismutase:

Back 8

SOD - converts the superoxide to H2O2.
There are 2 SOD - SOD1 is in teh cytosol and SOD2 is in the mitochondria.

Front 9

Catalase

Back 9

converts 2 H2O2 to 2H2O and O2.
catalase is a heme contain enzyme.

Front 10

Peroxiredoxins

Back 10

takes peroxide and turns it into water and O2.
selenium containing enzyme.

Front 11

Reductase

Back 11

reduces H2O2 to water while oxidizing GHS to GSSH (makes disulfide bond between 2 glutathione) The reductase reduces GSSH back to 2 GSH while oxidizing NADPH to NADP+

Front 12

Reductase and peroxiredoxins work together in a cycle to do what?

Back 12

to reduce H2O2 to water.

the reductase reduces GSSH to 2GSH.

Front 13

4 antioxidant enzymes

Back 13

reductase
SOD
peroxiredoxins
catalase

Front 14

2 antioxidant molecules:

Back 14

thiol antioxidants
phenolic antioxidant
B-carotene
Vitamen C

Front 15

thiol antioxidant molecules

Back 15

responsible for forming disulfide bonds.
EX: lipoic acid
glutathion (GSH)

Front 16

Phenolic antioxidants

Back 16

contain a phenol, the double bonds can stablize the radical. Lots of radical resonance structures.
EX: vit. E and CoQ

Front 17

B-carotene

Back 17

made of isoprenoid units and contains double bonds.

Front 18

Vit. C

Back 18

reversibly oxidized. it acts to oxidize other antioxidants expecially vit. E.

Front 19

Malaria is caused by several species of plasmodium.

Back 19

Mosquito transfers a sporoite into the blood, teh parasite proliferates in liver producing merozoites.

Merozoites invade RBC and feeds on Hb.

Front 20

Mech. that malarial parasite has to protect itself from ROS.

Back 20

merozoites convert heme to make a polymer called hemozoin.
FeII to FeIII to hemozoin.

SOD and catalyse converts ROS to less reactive species.

The GSH and thioreducine system protects by converting to H2O2.

Pentose Phosphate Pathway is only way to make NADPH that converts O2 to superoxide.

Front 21

Resistance to Malaria.

Back 21

if you have a defect enzyme G-6-P dehydrogenase then don't make G-6-P and cant enter the pentose pathway to you don;t get NADPH and dont make sureroxide radicals.

Front 22

Antimalaria Drug

Back 22

Chloroquine - inhibits product of hemozoin. So have more heme that makes the hydoxide radical and harms the parasite.

Artemesinin - forms carbon centered free radical the enteracts with Fe. Has an epoxide ring.

The drug breaks the epoxide ring and forms a oxide radical.