Comparison Note — Glycolysis vs TCA Cycle vs ETS — Notes | NoteTube

Feature	Glycolysis	TCA Cycle	ETS
Location	Cytoplasm	Mitochondrial matrix	Inner mitochondrial membrane
Substrate	Glucose (6C)	Acetyl CoA (2C)	NADH, $FADH_{2}$
End Products	2 Pyruvate, 2 ATP, 2 NADH	$CO_{2}$ , 6 NADH, 2 $FADH_{2}$ , 2 GTP	$H_{2}O$ , 34 ATP
$O_{2}$ requirement	Not required	Not directly required	$O_{2}$ is the final electron acceptor
Number of steps	10 enzymatic steps	8 enzymatic steps	4 complexes + 2 mobile carriers
Key enzymes	Hexokinase, PFK, Pyruvate kinase	Citrate synthase, Isocitrate DH, α-KG DH	NADH DH (CI), Succinate DH (CII), Cyt bc1 (CIII), Cyt c oxidase (CIV)
Nature	Catabolic only	Amphibolic	Catabolic (oxidative phosphorylation)
ATP type	Substrate-level phosphorylation	Substrate-level (GTP) + NADH/ $FADH_{2}$	Oxidative phosphorylation
Organism occurrence	All living cells	Aerobic cells only	Aerobic cells only
$CO_{2}$ released	None	Yes (4 $CO_{2}$ per glucose)	None