Pyruvate dehydrogenase activity during aerobic respiration requires

In $TCA$ cycle,how many reduced coenzymes are produced from one Acetyl $CoA$?

Respiratory enzymes are present in

Succinate dehydrogenase catalyzes the formation of

Describe the process occurring in the matrix of mitochondria.

Krebs' cycle was discovered by Krebs in pigeon muscles in $1940$. Which step is called gateway step/link reaction/transition reaction in respiration?