The entry of Na+ causes the opening of more voltage- gated Na+ channels and further depolarization, setting up a positive feedback loop .

TLS Online TPP Program

#Id: 3294

#Unit 6. System Physiology – Plant

Ubiquinone (Q) is reduced by four ways;

a. By the oxidation of NADH in complex I
b. Electrons from succinate pass through a flavoprotein with the cofactor FAD and several Fe-S
centers (in Complex II) on the way to Q
c. Glycerol 3-phosphate donates electrons to a flavoprotein (glycerol 3-phosphate dehydrogenase)
on the outer face of the inner mitochondrial membrane, from which they pass to Q.
d. Acyl-CoA dehydrogenase (the first enzyme of oxidation) transfers electrons to electron-
transferring flavoprotein (ETF), from which they pass to Q via ETF

TLS Online TPP Program

#Id: 3295

#Unit 6. System Physiology – Plant

Glycerol 3-phosphate shuttle
In the cytosol, dihydroxyacetone phosphate accepts two reducing equivalents from NADH in a reaction catalyzed by cytosolic glycerol 3-phosphate dehydrogenase

TLS Online TPP Program

#Id: 3296

#Unit 6. System Physiology – Plant

formation of ROS in two condition;
a) Mitochondria are not making ATP (for lack of ADP or O2) and therefore have a large proton-motive force and a high ratio of QH2/Q
b) there is a high NADH/NADratio in the matrix

TLS Online TPP Program

#Id: 3298

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 3300

#Unit 6. System Physiology – Plant

Mitochondria is an respirosome, so it can avail oxygen out of complex IV and the oxygen used in the ETS without complex IV, always get converted into ROS.

TLS Online TPP Program

#Id: 3302

#Unit 6. System Physiology – Plant

In actively respiring mitochondria, 0.1% to as much as 4% of the O2 used in respiration forms •O2^2- — more than enough to have lethal effects unless the free radical is quickly disposed of.