Which process breaks down nutrients to produce ATP and releases waste products in living cells?

• A. Photosynthesis
• B. Hess's Law
• C. Efficiency
• D. Cellular Respiration

Answer: (D)

Cellular respiration is the process that breaks down nutrients to harvest energy as ATP and releases waste products like carbon dioxide and water. Through glycolysis, the Krebs cycle, and the electron transport chain, nutrients are oxidized step by step, with most ATP produced during the electron transport chain, aided by oxygen as the final electron acceptor. This energy conversion powers cellular activities, and the waste products are expelled from the cell. This stands in contrast to photosynthesis, which uses light energy to build sugars, Hess's Law, which deals with enthalpy changes in reactions, and efficiency, a general measure of energy use that isn’t a metabolic pathway.