Which of the following processes occurs in the mitochondria?

Cellular respiration occurs in the mitochondria and is a crucial process for energy production in eukaryotic cells. This process involves several stages, primarily glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation, which includes the electron transport chain. Mitochondria are often referred to as the "powerhouses" of the cell because they convert energy stored in glucose and other nutrients into adenosine triphosphate (ATP), the energy currency used by cells to perform various functions.

In contrast, photosynthesis takes place in chloroplasts, primarily in plant cells. DNA replication occurs in the nucleus, where the cell’s genetic material is stored. Protein synthesis, which includes transcription and translation, takes place in the cytoplasm and on ribosomes, not within the mitochondria. Hence, cellular respiration is the only process listed that is directly associated with the mitochondria's role in generating ATP for cellular activities.