What is the Net ATP produced for Pyruvate Oxidation, Citric Acid Cycle, and Electron Transport Chain?
To determine the net ATP produced through Pyruvate Oxidation, Citric Acid Cycle, and Electron Transport Chain, we need to understand the step-by-step process involved in each pathway.
1. Pyruvate Oxidation:
Pyruvate Oxidation occurs in the mitochondria and involves the conversion of pyruvate, which is generated through glycolysis, into Acetyl-CoA. During this process, one molecule of CO2 is released for each pyruvate, and NAD+ is reduced to NADH. However, the direct production of ATP is not a part of this step.
2. Citric Acid Cycle (also known as Krebs cycle or Tricarboxylic Acid cycle):
The Citric Acid Cycle is a series of chemical reactions that takes place in the mitochondria matrix. During this cycle, Acetyl-CoA is oxidized into carbon dioxide, generating high-energy electron carriers such as NADH and FADH2. In addition, one molecule of ATP is directly produced through substrate-level phosphorylation. However, it's important to note that this ATP is not considered as a part of the net ATP produced from oxidative phosphorylation.
3. Electron Transport Chain (ETC):
The Electron Transport Chain occurs in the inner mitochondrial membrane. It is responsible for the final stage of cellular respiration, where the high-energy electron carriers (NADH and FADH2) from the previous steps are used to generate ATP through oxidative phosphorylation. As electrons pass through a series of protein complexes within the ETC, a proton gradient is created across the inner membrane. This gradient drives ATP synthase to produce ATP from ADP and inorganic phosphate (Pi). The exact number of ATP molecules produced per NADH or FADH2 can vary, but on average, NADH produces about 2.5-3 ATP molecules, while FADH2 produces about 1.5-2 ATP molecules.
In summary, from Pyruvate Oxidation, no ATP is directly produced, but NADH is generated. In the Citric Acid Cycle, one ATP is produced through substrate-level phosphorylation. The majority of ATP production happens in the Electron Transport Chain, where NADH and FADH2 generated through previous steps result in the production of a varying number of ATP molecules.
It's important to note that the exact number of ATP molecules produced during cellular respiration can vary due to factors like the maximum yield of the ETC, the number of proton pumps, etc. These values can change depending on cellular conditions or the organism under consideration.