In which part of the cell do the Krebs cycle and electron transport chain occur?

The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondria, which is often referred to as the powerhouse of the cell. This series of chemical reactions is essential for energy production, as it helps to convert biochemical energy from nutrients into adenosine triphosphate (ATP), the energy currency of the cell.

The electron transport chain, which follows the Krebs cycle, also takes place in the mitochondria, specifically along the inner mitochondrial membrane. This process utilizes the electrons generated through the Krebs cycle to create a proton gradient that drives ATP synthesis, making the mitochondria a critical site for cellular respiration and energy metabolism.

In contrast, the nucleus is the control center of the cell that houses genetic material, ribosomes are involved in protein synthesis and are found in the cytoplasm, and while some reactions of glycolysis do occur in the cytoplasm, neither the Krebs cycle nor the electron transport chain take place there. Thus, the correct location for both the Krebs cycle and the electron transport chain is indeed within the mitochondria.