Which material is needed for cellular respiration to happen?
A. Carbon dioxide
B. Glucose
C. Water
The correct answer and explanation is :
The correct answer is B. Glucose.
Cellular respiration is a metabolic process that occurs in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), which is the energy currency of the cell. The primary material needed for cellular respiration to occur is glucose, a form of sugar that provides the necessary energy for the cell.
Explanation of Cellular Respiration:
Cellular respiration takes place in three main stages: glycolysis, the citric acid cycle (also known as the Krebs cycle), and the electron transport chain.
- Glycolysis occurs in the cytoplasm of the cell. During this stage, one molecule of glucose (C6H12O6) is broken down into two molecules of pyruvate, releasing a small amount of energy in the form of ATP. This process does not require oxygen, so it can occur under both aerobic (with oxygen) and anaerobic (without oxygen) conditions. Glucose is the key substrate for this process.
- Citric Acid Cycle (Krebs Cycle) occurs in the mitochondria. The pyruvate produced from glycolysis is further broken down to release more energy in the form of high-energy electron carriers (NADH and FADH2), and carbon dioxide is produced as a byproduct.
- Electron Transport Chain occurs in the inner mitochondrial membrane. The NADH and FADH2 produced in the previous stages transfer their electrons to the electron transport chain. Oxygen is the final electron acceptor in this chain, and when combined with electrons and hydrogen, it forms water. This stage produces the majority of ATP, which is crucial for cellular functions.
Why Glucose?
Glucose is the primary fuel used in cellular respiration because it contains many bonds that store energy. When these bonds are broken down, they release energy that is captured and stored in ATP molecules. While oxygen and carbon dioxide are also involved in cellular respiration, they are not “materials” that are broken down to release energy. Oxygen acts as the final electron acceptor in the electron transport chain, and carbon dioxide is a byproduct of the process. Water is also produced, but it is a result of the reaction rather than a substrate.
Thus, glucose is the essential material needed for cellular respiration to occur effectively.