Final answer:
Cellular respiration primarily takes place in the mitochondria, with initial steps such as glycolysis occurring in the cytoplasm, followed by the Krebs cycle and oxidative phosphorylation within the mitochondria.
Step-by-step explanation:
Cellular respiration occurs predominantly in the mitochondria of eukaryotic cells. In the context of the options provided by a student, the correct answer is 2) Mitochondria. There are multiple stages to cellular respiration that involve different parts of the cell. Initially, glycolysis takes place in the cytoplasm, where glucose is split into two molecules of pyruvate. The pyruvate then enters the mitochondrion, where it undergoes an intermediate step of being converted into Acetyl CoA. The next major phase is the Krebs cycle (also known as the citric acid cycle), which occurs in the mitochondrial matrix. This process is followed by the electron transport chain, where oxidative phosphorylation takes place on the inner mitochondrial membrane, leading to the production of ATP.