Final answer:
The Krebs cycle produces CO2, NADH, FADH2, and ATP (or GTP) for each acetyl-CoA that enters the cycle. It turns twice for each glucose molecule that initiates glycolysis, resulting in doubled yields of these products.
Step-by-step explanation:
The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is a key component of cellular respiration. In this cycle, each pyruvate molecule from glycolysis is first converted into a two-carbon molecule known as acetyl-CoA. The acetyl-CoA then enters the Krebs cycle and is further processed, leading to the production of CO2, and high-energy molecules such as NADH, FADH2, and ATP or GTP (equivalent to ATP in some organisms). During one turn through the cycle, the main outputs are:
- Two molecules of CO2 (carbon dioxide)
- Three molecules of NADH
- One molecule of FADH2
- One molecule of ATP or GTP through substrate-level phosphorylation
As the Krebs cycle turns twice per glucose molecule entering glycolysis, the eventual yield is doubled. Overall, the cycle plays an essential role in cellular energy production by transferring electrons to the electron transport chain, where most ATP is generated.