Science Order and Design Test 1 Practice

The function being tested is the mitochondria’s role as the cell’s energy powerhouse: they generate most of the cell’s ATP through cellular respiration. In this process, glucose is broken down step by step, with the bulk of ATP produced when electrons are transferred through the electron transport chain in the inner mitochondrial membrane. The energy from this flow pumps protons to create a gradient, and ATP synthase uses that gradient to convert ADP and inorganic phosphate into ATP. This ATP provides the energy for most cellular activities, making mitochondrial ATP production the central job.

Other options point to roles of different parts of the cell. Storing genetic information mainly involves the nucleus (mitochondria do contain their own DNA, but their primary function isn’t genetic storage). Synthesizing proteins for secretion is primarily handled by ribosomes and the secretory pathway, not the mitochondria. Photosynthesis is carried out by chloroplasts in plants, not mitochondria, which instead supply the energy currency used in virtually all cells.