Why is glucose the most important & biologically relevant carbohydrate?

• A. It's the central carbohydrate in metabolism & energy production for nearly all life, including humans.
• B. It provides the most energy/gram of any macronutrient.
• C. It is broken down into smaller molecules & stored in the liver.
• D. It is the only type of sugar that humans can digest.

Answer: (A)

Verified step by step guidance

1. Glucose is the most important carbohydrate because it serves as the primary energy source for nearly all living organisms, including humans. It is central to metabolism and energy production.
2. Glucose provides 4 kcal/gram, which is the standard energy yield for carbohydrates. While fats provide more energy per gram (9 kcal/gram), glucose is more readily utilized by the body for immediate energy needs.
3. In the body, glucose is broken down through glycolysis, a metabolic pathway that converts glucose into pyruvate, producing ATP (adenosine triphosphate), the energy currency of the cell.
4. Excess glucose can be stored in the liver and muscles as glycogen through a process called glycogenesis. This stored glycogen can be broken down later to release glucose when energy is needed.
5. While glucose is not the only sugar humans can digest, it is the most biologically relevant because it is the primary sugar used in cellular respiration and is essential for brain function, as the brain relies almost exclusively on glucose for energy under normal conditions.