In which process are glucose and oxygen the reactants?
A. Photosynthesis B. Cellular respiration C. ATP Production D. ADP production
The correct answer and explanation is:
The correct answer is B. Cellular respiration.
Cellular respiration is the process where glucose and oxygen are used as reactants to produce energy in the form of ATP (adenosine triphosphate). This is a fundamental biochemical pathway in both plants and animals, occurring in the mitochondria of eukaryotic cells.
In cellular respiration, glucose (C6H12O6) undergoes a series of reactions, starting with glycolysis in the cytoplasm. During glycolysis, glucose is broken down into two molecules of pyruvate, releasing a small amount of energy. This process does not require oxygen and is therefore considered anaerobic. If oxygen is present, the pyruvate enters the mitochondria, where it undergoes further oxidation in the citric acid cycle (also known as the Krebs cycle). Here, pyruvate is completely broken down, releasing carbon dioxide, water, and high-energy electrons.
The high-energy electrons are then transferred to the electron transport chain, a series of protein complexes embedded in the inner mitochondrial membrane. As electrons move through the electron transport chain, energy is released and used to pump protons (H+) across the mitochondrial membrane, creating a proton gradient. The return flow of protons through ATP synthase drives the production of ATP from ADP (adenosine diphosphate) and inorganic phosphate. Oxygen is the final electron acceptor in the electron transport chain, combining with the electrons and protons to form water.
Thus, glucose and oxygen are both essential reactants in cellular respiration. Glucose provides the carbon backbone and energy needed for the reactions, while oxygen acts as the final electron acceptor, allowing the process to proceed efficiently and generate the energy required for cellular activities. This process produces about 36 molecules of ATP per molecule of glucose, providing the energy necessary for life.