During which step of cellular respiration is carbon dioxide released?
Carbon dioxide is released during the step of cellular respiration called the Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle.
Carbon dioxide is released during the third step of cellular respiration, which is called the Krebs cycle or the citric acid cycle. In this cycle, carbon dioxide is produced as a byproduct when acetyl-CoA molecules are broken down into carbon dioxide, ATP, and electron carriers (NADH and FADH2). The carbon dioxide is then released into the surrounding environment, while the other products continue on to the next step of cellular respiration.
Carbon dioxide is released during the process of cellular respiration in the step called the Krebs cycle, also known as the citric acid cycle or the TCA cycle (tricarboxylic acid cycle). The Krebs cycle is the second stage of cellular respiration and takes place in the mitochondria of the cell.
To understand how carbon dioxide is released during this step, let's break down the process:
1. Glycolysis: The first step of cellular respiration is glycolysis, which occurs in the cytoplasm. During glycolysis, glucose molecules are converted into two molecules of pyruvate, generating a small amount of ATP and NADH.
2. Pyruvate Decarboxylation: After glycolysis, the pyruvate molecules enter the mitochondria. Before entering the Krebs cycle, each pyruvate molecule is converted into acetyl CoA (acetyl coenzyme A) in a process called pyruvate decarboxylation. During this conversion, a carbon atom from each pyruvate molecule is released as carbon dioxide (CO2), and the remaining two-carbon molecule combines with Coenzyme A to form acetyl CoA.
3. Krebs Cycle: Once the pyruvate is converted into acetyl CoA, it enters the Krebs cycle. In this step, the acetyl CoA combines with a four-carbon molecule called oxaloacetate to form citrate. Through a series of chemical reactions, citrate is metabolized, releasing two molecules of carbon dioxide in the process. These released carbon dioxide molecules are waste products and are exhaled as a byproduct of respiration.
So, to summarize, carbon dioxide is released during the Krebs cycle, which is the second stage of cellular respiration, and occurs in the mitochondria of the cell. During pyruvate decarboxylation, carbon dioxide is released as a byproduct before the pyruvate molecules enter the Krebs cycle.