ETC and TCA enzymes occur in

ETC and TCA enzymes occur in Mitochondria.
The ETC is embedded within the extensive inner membrane of the mitochondrion, near the mitochondrial matrix in which the TCA cycle is localized.
In a series of enzymatic reactions, the TCA cycle generates the reducing equivalents NADH and FADH2, which are required to transfer electrons to the mitochondrial respiratory chain, also known as the electron transport chain (ETC).