The high-energy electrons from the Krebs cycle (also known as the citric acid cycle) don't disappear. Instead, they are transferred to electron carriers, namely NAD+ and FAD.

Here's what happens:

1. Krebs Cycle: During the Krebs cycle, several reactions occur that release energy. This energy is used to convert NAD+ into NADH and FAD into FADH2. These molecules now carry the high-energy electrons.

2. Electron Transport Chain: NADH and FADH2 then move to the electron transport chain (ETC) in the mitochondria. Here, the high-energy electrons are passed from one protein complex to another down the chain.

3. Energy Release: As the electrons move down the ETC, energy is released. This energy is used to pump protons (H+) across the inner mitochondrial membrane, creating a concentration gradient.

4. ATP Production: The proton gradient then drives the enzyme ATP synthase, which uses the potential energy stored in the gradient to produce ATP (adenosine triphosphate), the primary energy currency of cells.

In essence, the high-energy electrons from the Krebs cycle are used as a source of energy to drive the electron transport chain and ultimately generate ATP through oxidative phosphorylation.