skanowanie0020

I

Outer mitocnonariai

membranę    acceptor of

electrons from NADH or FADH₂

A Figurę 15-9 Outiine of the major metabolic reacrions in mitochondria. The substrates of oxidative phosphorylation— pyruvare, farty adds, ADP, and P_;—are transported to the matrix from the cytosol by permeases; G? diffuses into the matrix. NADH, which is generated in the cytosol during giy-coiysis, is not transported directły to the matrix because the inner tnembrane is impermeabłe to NAD^ or NADK; in-stead, a shuttle system (see Figurę 15-21) transports electrons from cytosolic NADH to the ełectron transport chain. ATP is transported to the cytosol in exchange for ADP and P_{, CO2 diffuses into the cytosol across the mitochondrial membranes. HSCoA. denotes free coenzyme A (CoA), and SCoA denótes CoA when it is esterified (see Figurę 15-11).

NADH

/ 2e

Succinate-		■r—* Fumarate
	2e i	2H‘^!"
FADH2	FAD i	Succinate-CoQ reductase
	FeS	complex
FAD ^
MN -« FeS --	CoQ	->■ Cyt b —

FeS

NADH-CoQ

reductase

complex

Cyt Ci

Cyt c

NAD

CoOHj-cyi c reeuesase comoiex

H-_;

H',

A Figurę 15-23 The flow of electrons from NADH, succi-nate, and FADH? to Oi (arrews) and the three sites for pamping protons across the inner mitochondrial membranę. The rour ełectron transport compiexes (orange) are integrai parts of the inner membranę and contain che specific ełectron carriers indicated. Ubiąuinone (coenzyme Q) and cyrochrome c are also associaced with the membranę. FMN is a cofactor rełated to FAD (see Figurę 15-10) that contains oniy the f!avin-ribose phosphate part of FAD.

Cyt a - Cyt a₃ -

Cyt c oxidase compiex

Cu

2<?

2H- -t- V20₂

“ H₂0