Which is the body's primary source of energy?

Which is the body's primary source of energy?

• A. Insulin
• B. Glucose
• C. Electrolytes
• D. Protein

Answer: (B)

Glucose is the body's primary energy source. Cells convert glucose into ATP through glycolysis, the citric acid cycle, and oxidative phosphorylation, providing quick, efficient fuel for most tissues during everyday activity. The brain relies heavily on glucose for its function, and while other fuels can be used under certain conditions, glucose remains the main energy source under normal circumstances. Insulin is a hormone that helps body tissues take up glucose from the bloodstream; it’s not a fuel itself. Electrolytes are minerals essential for nerve signaling, muscle function, and fluid balance, not energy sources. Protein can supply energy, but only when carbohydrate stores are limited; its primary roles are building and repairing tissues and making enzymes and hormones. Therefore, glucose stands out as the body's main energy source.

Glucose is the body's primary energy source. Cells convert glucose into ATP through glycolysis, the citric acid cycle, and oxidative phosphorylation, providing quick, efficient fuel for most tissues during everyday activity. The brain relies heavily on glucose for its function, and while other fuels can be used under certain conditions, glucose remains the main energy source under normal circumstances.

Insulin is a hormone that helps body tissues take up glucose from the bloodstream; it’s not a fuel itself. Electrolytes are minerals essential for nerve signaling, muscle function, and fluid balance, not energy sources. Protein can supply energy, but only when carbohydrate stores are limited; its primary roles are building and repairing tissues and making enzymes and hormones. Therefore, glucose stands out as the body's main energy source.