In the first half of the Citric acid cycle, ____________ is oxidized, yielding a pair of electrons that reduce a molecule of NAD to NADH. Succinate is oxidized to fumarate using ____________ as the electron acceptor. A 2-carbon group from ____________ enters the cycle. A second oxidation produces ____________ and 2 electrons. Malate is oxidized, yielding a 4-carbon molecule of ____________ and two electrons.