In the citric acid cycle, there is only one reaction which
indirectly produces an ATP and this is at step 7.
Connections to Electron Transport and ATP:
Reactions 4, 6, and 10 involve oxidations of an alcohol group
to a ketone group with the coenzyme NAD+, which result
in the removal of 2 hydrogens and 2 electrons. This is the entry
point into electron transport chain. Recall that starting with
NAD+, results in the production of 3 ATP for each
use of the electron transport chain.
How many ATP are produced from one turn of the citric acid
cycle starting with NAD+ in the electron transport
Steps 4 = NAD+ = 3 ATP
Steps 6 = NAD+ = 3 ATP
Steps 10 = NAD+ = 3 ATP
NET ATP from = NAD+ = 9 ATP
Step 8 is another oxidation involving the coenzyme FAD. Since
FAD is part of the second enzyme complex, only 2 ATP are made
with the electron transport chain.
Step 8 = FAD = 2 ATP