Question

which carbohydrate can be used by the body as an immediate source of energy?
glucose
cellulose
chitin
glycogen

Explanation:

• Glucose is a simple sugar (monosaccharide) that can be directly used in cellular respiration (specifically glycolysis) to produce ATP (adenosine triphosphate), the energy - currency of the cell.
• Cellulose is a structural polysaccharide in plant cell walls and cannot be digested by humans (we lack the enzyme cellulase), so it cannot be used as an energy source.
• Chitin is a structural polysaccharide found in the exoskeletons of arthropods and cell walls of fungi. Humans do not have the ability to break it down for energy.
• Glycogen is a storage polysaccharide in animals. While it can be broken down into glucose units (through glycogenolysis), it is not an immediate source like glucose. Glucose is already in a form that can be quickly metabolized.

Answer:

glucose