Final answer:
The inputs of cellular respiration are oxygen and glucose. These react to form carbon dioxide, water, and ATP through three stages: Glycolysis, the Citric Acid Cycle, and Oxidative Phosphorylation. The carbon atoms from glucose end up as carbon dioxide, which is exhaled as a waste product.
Step-by-step explanation:
The molecules that are inputs in cellular respiration are oxygen and glucose. During cellular respiration, glucose, which is a six-carbon molecule, gets broken down, and each carbon atom becomes part of a molecule of carbon dioxide, which is then expelled from the body as waste. This process happens in three stages: Glycolysis, the Citric Acid Cycle (also known as Krebs Cycle), and Oxidative Phosphorylation (or Electron Transport Chain).
Glycolysis occurs in the cytoplasm and does not require oxygen, breaking glucose into two molecules of pyruvate. The Citric Acid Cycle takes place inside mitochondria and requires oxygen to produce energy-rich electron carriers. Oxidative Phosphorylation then uses these carriers to create ATP, the energy currency of the cell, via a process called chemiosmosis.
During these stages, the reactants, oxygen and glucose, are converted into carbon dioxide, water, and ATP. The oxygen that the organism breathes in is critically important in the Electron Transport Chain, where it serves as the final electron acceptor, combining with electrons and hydrogen ions to form water. The energy from these reactions is stored in ATP molecules, providing energy for various cellular activities.