The compound derived from glucose that actually enters the Krebs cycle is acetyl-CoA.

Here's how it happens:

1. Glycolysis: Glucose is broken down into pyruvate.

2. Pyruvate Oxidation: Pyruvate is converted into acetyl-CoA. This process occurs in the mitochondria and involves the removal of a carbon dioxide molecule from pyruvate and the addition of coenzyme A.

3. Krebs Cycle: Acetyl-CoA enters the Krebs cycle, also known as the citric acid cycle, where it is further oxidized to produce ATP, NADH, and FADH2, which are used to generate more ATP in the electron transport chain.

So, while glucose itself doesn't directly enter the Krebs cycle, it is broken down into pyruvate, which is then converted into acetyl-CoA, the compound that actually fuels the cycle.