Krebs cycle takes place in

When $1$ molecule of pyruvic acid passes through the process of the Krebs cycle,$a$ molecules of $CO_2$ are released and at $b$ different stages $2H^+$ and $c$ electrons are released. Identify $a, b, c$.

The mineral activator required for the enzyme isocitrate dehydrogenase of the $TCA$ cycle is

$TCA$ cycle is a

How many $ATP$ molecules are produced by substrate-level phosphorylation during the complete oxidation of one molecule of pyruvic acid?

Do you know any step in the $TCA$ cycle where there is substrate-level phosphorylation? Which one?