Final answer:
To obtain energy from starch and glycogen, the body starts with digestion, breaking them down into glucose, which is then used in glycolysis to produce ATP, the energy currency of the cell.
Step-by-step explanation:
To obtain energy from starch and glycogen, the body must begin by breaking these complex carbohydrates down into simpler forms during the process of digestion. Starch and glycogen are broken down into glucose, the most readily available source of energy for cells.
The digestion of carbohydrates starts in the mouth with the action of salivary amylase breaking down starches. As digestion continues in the small intestine, enzymes further break down carbohydrates into monosaccharides. Once these sugars are absorbed across the intestinal epithelium, they can enter the circulatory system and be transported to the liver and other tissues.
In the body's cells, glucose undergoes a metabolic pathway known as glycolysis, where it is oxidized to produce adenosine triphosphate (ATP), the energy currency of the cell. This process is essential for providing the energy necessary for many physiological functions.