In which process are the products of the reaction glucose and oxygen?
A. photosynthesis B. cellular respiration C. ATP production D. ADP production
The correct answer and explanation is:
The correct answer is B. cellular respiration.
Explanation:
Cellular respiration is the process by which cells convert glucose into usable energy, specifically in the form of ATP (adenosine triphosphate), while releasing carbon dioxide and water as byproducts. This process occurs in both plant and animal cells. During cellular respiration, glucose (C₆H₁₂O₆) and oxygen (O₂) are the primary reactants. These two reactants undergo a series of metabolic steps, ultimately producing ATP, which cells use to perform various functions.
The process can be broken down into several stages:
- Glycolysis: This occurs in the cytoplasm of the cell. A single molecule of glucose is split into two molecules of pyruvate, producing a small amount of ATP and NADH in the process. Oxygen is not required for glycolysis.
- Pyruvate Decarboxylation and Citric Acid Cycle (Krebs Cycle): If oxygen is available, the pyruvate molecules move into the mitochondria. Here, they are further processed and broken down into carbon dioxide, which is released as a waste product. In this stage, energy-rich molecules like NADH and FADH₂ are produced, which will be used in the next stage.
- Oxidative Phosphorylation (Electron Transport Chain and Chemiosmosis): In the inner mitochondrial membrane, NADH and FADH₂ donate electrons to the electron transport chain. This process ultimately leads to the production of a large amount of ATP through chemiosmosis. Oxygen acts as the final electron acceptor in this stage, combining with electrons and hydrogen ions to form water (H₂O).
Thus, oxygen is essential in the final stage of cellular respiration to help generate a significant portion of ATP. Glucose, on the other hand, is the fuel that is broken down in the initial stages, providing the necessary energy to power the reactions.
In contrast, photosynthesis (option A) produces glucose and oxygen, but it occurs in plants and some other organisms and is the opposite process to cellular respiration.