Anatomy and Physiology II Practice Test

In which part of the cell does the citric acid cycle occur?

1. Cytoplasm

2. Ribosome

3. Nucleus

4. Mitochondria

The correct answer is: Mitochondria

The citric acid cycle, also known as the Krebs cycle or TCA cycle, occurs in the mitochondria of eukaryotic cells. This is a key metabolic pathway that plays an essential role in cellular respiration, where it serves to oxidize acetyl-CoA to produce energy in the form of ATP, as well as electron carriers like NADH and FADH2. The mitochondria, often referred to as the powerhouse of the cell, are specifically adapted for producing energy. They contain the necessary enzymes and the appropriate environment for the reactions of the citric acid cycle to take place efficiently. Other parts of the cell, such as the cytoplasm, ribosome, and nucleus, do not facilitate this cycle, as they are associated with different functions such as protein synthesis, genetic material storage, and various metabolic processes that do not involve the cycle directly.