Which part of cellular respiration produces the most ATP?
1 point
glycolysis
fermentation
Krebs cycle
Electron Transport Chain
Electron Transport Chain
The Electron Transport Chain (ETC) produces the most ATP during cellular respiration. The ETC is the final stage of cellular respiration and occurs in the inner mitochondrial membrane in eukaryotic cells. The ETC uses energy carriers such as NADH and FADH2, which are produced in the previous stages of cellular respiration (glycolysis and the Krebs cycle), to transport electrons along a series of protein complexes. As electrons pass through these complexes, they trigger the pumping of protons (H+) across the mitochondrial membrane, creating an electrochemical gradient. This gradient then drives the synthesis of ATP through a protein called ATP synthase. Overall, the production of ATP during the ETC is significantly higher than in the other stages of cellular respiration.
The part of cellular respiration that produces the most ATP is the Electron Transport Chain (ETC). The ETC is the final step in cellular respiration and is located in the inner membrane of the mitochondria.
To understand why the ETC produces the most ATP, let's take a step-by-step approach of how ATP is generated during cellular respiration:
1. Glycolysis: This is the initial step of cellular respiration that occurs in the cytoplasm. During glycolysis, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH. However, the majority of ATP is not generated in glycolysis.
2. Fermentation: This occurs in the absence of oxygen and is an anaerobic process. Fermentation helps regenerate NAD+ so that glycolysis can continue to produce ATP. However, fermentation does not directly produce a significant amount of ATP.
3. Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle): This is the second stage of cellular respiration and takes place in the matrix of the mitochondria. The Krebs cycle produces a few more molecules of ATP, as well as NADH and FADH2, which will be utilized in the ETC. However, the ATP production in this step is still relatively low compared to the ETC.
4. Electron Transport Chain (ETC): The ETC is the site where the majority of ATP is produced. It consists of a series of protein complexes embedded in the inner membrane of the mitochondria. The NADH and FADH2 generated in the previous steps carry high-energy electrons to the ETC. As electrons pass through the protein complexes, they create a flow of protons (H+) across the inner mitochondrial membrane, forming a proton gradient. This gradient drives ATP synthesis through a protein called ATP synthase. The combination of the proton gradient and ATP synthase leads to the production of a large number of ATP molecules.
In summary, while each step of cellular respiration contributes to the production of ATP, the Electron Transport Chain generates the most ATP molecules.