Which are the three stages of cellular respiration?

Which are the three stages of cellular respiration?

• A. Glycolysis, Calvin cycle, electron transport chain
• B. Glycolysis, Krebs cycle, electron transport chain
• C. Glycolysis, fermentation, citric acid cycle
• D. Glycolysis, oxidative phosphorylation, chemiosmosis

Answer: (B)

The correct answer identifies the three primary stages of cellular respiration as glycolysis, the Krebs cycle, and the electron transport chain. Glycolysis is the first step in the breakdown of glucose, occurring in the cytoplasm of the cell, where one molecule of glucose is converted into two molecules of pyruvate, producing a small amount of ATP and NADH in the process. Following glycolysis, the Krebs cycle (also known as the citric acid cycle) occurs in the mitochondria. This stage processes the pyruvate further, generating additional NADH and FADH2 while releasing CO2 as a byproduct. These electron carriers are essential for the next stage. The final stage, the electron transport chain, takes place in the inner mitochondrial membrane. Here, the electrons from NADH and FADH2 are transferred through a series of proteins, leading to the generation of ATP through oxidative phosphorylation. This stage is critical for the majority of ATP produced during cellular respiration. The other choices include components that do not accurately represent the stages of cellular respiration. For instance, the Calvin cycle is part of photosynthesis, fermentation is an alternative metabolic process that occurs in the absence of oxygen and is typically considered a separate pathway, and oxidative

The correct answer identifies the three primary stages of cellular respiration as glycolysis, the Krebs cycle, and the electron transport chain.

Glycolysis is the first step in the breakdown of glucose, occurring in the cytoplasm of the cell, where one molecule of glucose is converted into two molecules of pyruvate, producing a small amount of ATP and NADH in the process.

Following glycolysis, the Krebs cycle (also known as the citric acid cycle) occurs in the mitochondria. This stage processes the pyruvate further, generating additional NADH and FADH2 while releasing CO2 as a byproduct. These electron carriers are essential for the next stage.

The final stage, the electron transport chain, takes place in the inner mitochondrial membrane. Here, the electrons from NADH and FADH2 are transferred through a series of proteins, leading to the generation of ATP through oxidative phosphorylation. This stage is critical for the majority of ATP produced during cellular respiration.

The other choices include components that do not accurately represent the stages of cellular respiration. For instance, the Calvin cycle is part of photosynthesis, fermentation is an alternative metabolic process that occurs in the absence of oxygen and is typically considered a separate pathway, and oxidative