When is CO2 generated during processes involved in ATP synthesis? During the electron transport system During glycolysis In the final step of oxidative phosphorylation When pyruvic acid enters the Krebs cycle and during the Krebs cycle the final step of the TCA cycle
CO2 is generated during the final step of oxidative phosphorylation. This occurs in the electron transport system when electrons are transferred through the electron carriers and ultimately combine with oxygen to form water. Additionally, CO2 is also produced when pyruvic acid enters the Krebs cycle and during the Krebs cycle itself, which is part of aerobic respiration and occurs in the mitochondria.
CO2 is generated during two main processes involved in ATP synthesis: the Krebs cycle and oxidative phosphorylation.
1. During the Krebs cycle: Pyruvic acid, produced during glycolysis, enters the mitochondria and is converted to Acetyl-CoA, which then enters the Krebs cycle. In the Krebs cycle, Acetyl-CoA undergoes a series of reactions that produce ATP and other energy-rich molecules. In one of the steps, a carbon atom is released as CO2, creating a molecule called citric acid. This CO2 release occurs twice per one glucose molecule since two molecules of Acetyl-CoA are produced from one glucose molecule.
2. During oxidative phosphorylation: The electron transport system is a part of oxidative phosphorylation, which occurs in the inner mitochondrial membrane. In this process, electrons from NADH and FADH2 (produced during earlier stages of glucose metabolism) are transferred along a series of protein complexes, creating an electron gradient. The final acceptor of these electrons is Oxygen (O2), which combines with hydrogen ions (H+) to form water (H2O). However, during this process, some electrons can escape from the transport chain and react with O2, generating free radicals. To mitigate this, some electrons react with molecular O2 to produce water, while others react with O2 to form CO2. The CO2 generated in this step is released as a waste product.
So, to summarize, CO2 is generated during the Krebs cycle when pyruvic acid enters the cycle and during oxidative phosphorylation in the final step of the electron transport system.