what is the third step in cellular resperation
The third step in cellular respiration is the citric acid cycle, also known as the Krebs cycle.
The third step in cellular respiration is the Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle. This cycle takes place in the mitochondria of cells and involves a series of chemical reactions that break down Acetyl-CoA, a molecule derived from glucose metabolism, to produce energy-rich molecules such as NADH and FADH2. The Krebs cycle completes the oxidation of glucose and generates energy in the form of ATP molecules through a process called oxidative phosphorylation.
The third step in cellular respiration is the Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle. To understand how to get to this step, let's go through the process of cellular respiration:
1. Glycolysis: This is the first step of cellular respiration, which occurs in the cytoplasm of the cell. During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate. This process produces a small amount of ATP (energy) and NADH (a coenzyme).
2. Pyruvate oxidation: This step takes place in the mitochondria. The pyruvate molecules produced in glycolysis are transported into the mitochondria, where they are further broken down into Acetyl CoA. This process generates NADH and releases carbon dioxide.
3. Krebs cycle: The third step, also known as the citric acid cycle, takes place in the mitochondria. Acetyl CoA enters the cycle, where it is combined with oxaloacetate to form citrate. Through a series of enzymatic reactions, citrate is gradually converted back into oxaloacetate. This cycle generates high-energy electron carriers, such as NADH and FADH2, as well as a small amount of ATP.
4. Electron transport chain (ETC): This is the final step of cellular respiration, which occurs in the inner mitochondrial membrane. The high-energy electron carriers (NADH and FADH2) produced in the previous steps donate their electrons to the ETC. Along the electron transport chain, the electrons flow through a series of protein complexes, generating a proton gradient across the membrane. This gradient is then used by ATP synthase to produce ATP through a process called oxidative phosphorylation.
So, to answer your question, the third step in cellular respiration is the Krebs cycle. It is important to note that cellular respiration is a complex process, and each step relies on the preceding steps for the production of ATP and the generation of high-energy electron carriers.