What process do cells use to obtain energy from food?

Cells obtain energy from food primarily through cellular respiration. This is the process in which cells convert glucose and oxygen into energy, water, and carbon dioxide. Cellular respiration occurs in several stages, including glycolysis, the Krebs cycle, and oxidative phosphorylation, all of which take place in the cytoplasm and mitochondria of the cells. During this process, the chemical energy stored in glucose is transformed into usable energy in the form of adenosine triphosphate (ATP), which powers various cellular activities.

While photosynthesis is the process used by plants to convert sunlight into glucose, it is not applicable to how animal cells obtain energy. Fermentation is an alternative process used in low-oxygen conditions and can produce energy without the use of oxygen, but it is not the primary method for energy production in most cells, especially in aerobic conditions. Osmosis is the movement of water across a semi-permeable membrane and does not directly relate to energy production from food. Therefore, cellular respiration is the most accurate answer for how cells derive energy from food.