National League for Nursing (NLN) Science Practice Exam

What is the primary source of energy for cellular processes?

1. Amino acids

2. Fatty acids

3. Glucose

4. Nucleotides

The correct answer is: Glucose

Glucose is considered the primary source of energy for cellular processes because it is highly efficient and readily metabolized by cells through cellular respiration. During this process, glucose undergoes glycolysis, the Krebs cycle, and oxidative phosphorylation, leading to the production of adenosine triphosphate (ATP), which powers various cellular functions. Glucose is abundant and can be easily derived from dietary carbohydrates, making it a crucial energy substrate for cells, especially those in high-demand organs such as the brain and muscles. This preferential use of glucose reflects its role in maintaining proper physiological functions, particularly in energy-demanding situations. While amino acids, fatty acids, and nucleotides serve important roles in metabolism and cellular processes, they are typically utilized for other functions. Amino acids are primarily used for protein synthesis and can be converted to glucose via gluconeogenesis when needed. Fatty acids are mainly stored as triglycerides and contribute to energy production through beta-oxidation, but this process is less immediate compared to glucose metabolism. Nucleotides play critical roles in cellular signaling and the synthesis of nucleic acids but are not utilized as primary energy sources. Therefore, glucose stands out as the primary and most efficient energy source for cellular processes.