Questions: Checkpoint question Of the three main stages of cellular respiration, which one does not take place in the mitochondria?

The answer is Glycolysis.

Explanation: Cellular respiration consists of three main stages: Glycolysis, the Citric Acid Cycle (also known as the Krebs Cycle), and the Electron Transport Chain.

1. Glycolysis: This stage occurs in the cytoplasm of the cell, not in the mitochondria. During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH in the process.

2. Citric Acid Cycle (Krebs Cycle): This stage takes place in the mitochondrial matrix. Here, the pyruvate produced in glycolysis is further broken down, generating more NADH and FADH2, as well as a small amount of ATP.

3. Electron Transport Chain: This stage occurs in the inner mitochondrial membrane. The NADH and FADH2 produced in the previous stages donate electrons to the electron transport chain, which drives the production of a large amount of ATP through oxidative phosphorylation.

Summary: Glycolysis is the stage of cellular respiration that does not take place in the mitochondria; it occurs in the cytoplasm.