Enzymes of electron transport system are present in
a)	Inner mitochondrial membrane	b)	Matrix
c)	Intermembranous space	d)	Endoplasmic reticulum

(a)

In eukaryotes, electron transport and oxidative phosphorylation occur in the inner membrane of mitochondria. The significant enzymes of inner mitochondrial membrane are enzymes of  electron transport pathways viz. NAD, FAD, DPN (diphosphopyridine nucleotide) dehydrogenase, five cytochromes (cytochrome-b, cytochrome-c, cytochrome-, cytochromes-a and cytochrome-), ubiquinone or coenzyme-, non-haem copper and iron, ATP synthetase, succinate fatty acid acyl transferase.