What is the primary source of energy for cellular processes?

ATP, or adenosine triphosphate, is the primary source of energy for cellular processes. It serves as the energy currency of the cell, facilitating a wide variety of biochemical reactions. When ATP is hydrolyzed, it releases energy that can be harnessed for processes such as muscle contraction, active transport of molecules across cell membranes, and biochemical synthesis.

Inside cells, ATP is generated from nutrients, particularly glucose, during cellular respiration. Glucose undergoes glycolysis, the citric acid cycle, and oxidative phosphorylation, ultimately leading to the production of ATP. However, while glucose is a significant energy source, it is the ATP molecules that directly power cellular activities.

Other options, such as ADP, are involved in the energy transfer process but do not serve as the primary energy source. ADP can be converted back into ATP through phosphorylation, but it is not the energy-utilizing form. Similarly, NADH plays a critical role in cellular respiration by acting as an electron carrier in redox reactions, but it does not provide energy in the same direct manner as ATP.

In summary, while glucose is crucial for the energy supply, ATP is the molecule that cells actively use to conduct energy-requiring functions, making it the definitive primary