AP BIOLOGY

Detailed explanation-1: -NADH and FADH2 made in the citric acid cycle (in the mitochondrial matrix) deposit their electrons into the electron transport chain at complexes I and II, respectively. This step regenerates NAD+ and FAD (the oxidized carriers) for use in the citric acid cycle.

Detailed explanation-2: -Transport of electrons from FADH2. Electrons from succinate enter the electron transport chain via FADH2 in complex II. They are then transferred to coenzyme Q and carried through the rest of the electron transport chain as described in Figure 10.8.

Detailed explanation-3: -NADH and FADH2 molecules formed during Glycolysis and Krebs Cycle carry their electrons to the electron transport chain. The electron transport chain creates a proton gradient that ultimately leads to the production of a large amount of ATP.

Detailed explanation-4: -Within the mitochondrial matrix, the reactions of the Krebs cycle adds electrons and protons to a number of electron carriers, which are then used by the electron transport chain to produce ATP.

Detailed explanation-5: -Energy from NADH and FADH2, which result from glycolysis and the Krebs cycle, is transferred to ATP. After passing through the electron transport chain, the “spent” electrons combine with oxygen to form water. This is why oxygen is needed; in the absence of oxygen, this process cannot occur.