What process do cells use to convert glucose into energy in the presence of oxygen?

Cells convert glucose into energy through a process known as cellular respiration. This metabolic pathway involves a series of reactions through which glucose is broken down to produce adenosine triphosphate (ATP), the energy currency of the cell. Cellular respiration occurs in three main stages: glycolysis, the Krebs cycle (also known as the citric acid cycle), and the electron transport chain.

In the presence of oxygen, this process is highly efficient, allowing cells to extract a maximum amount of energy from glucose. Oxygen acts as the final electron acceptor in the electron transport chain, facilitating the conversion of energy stored in glucose into a usable form. The byproducts of this process are carbon dioxide and water, which are expelled from the cell and the organism.

This contrasts with fermentation, which is an anaerobic process that occurs in the absence of oxygen and produces much less energy. Photosynthesis, on the other hand, is the process by which plants, algae, and some bacteria convert light energy into chemical energy storage in glucose, and it is not a direct method for energy extraction from glucose. Lipid synthesis refers to the production of lipids or fats, which is a separate metabolic pathway and not directly related to glucose metabolism for energy.