Final answer:
Glucose is a vital energy source for the human body, obtained either directly from food or from stored glycogen. The liver regulates blood glucose levels, while cells convert glucose into ATP for energy. Insulin is key in managing glucose uptake and storage.
Step-by-step explanation:
Glucose is essential for the human body as it is the most readily available source of energy. Through the process of digestion, complex carbohydrates are broken down into simple sugars such as glucose. Once in the bloodstream, glucose can be directed for immediate use or stored as glycogen in the liver and muscles. The liver plays a key role in regulating glucose levels in the blood.
When cells need energy, glucose is metabolized during glycolysis to produce ATP, which is the main energy currency of cells. The availability of glucose is critical before glycolysis can commence, which can be obtained via dietary sources or stored glycogen. Foods like fruit, honey, and refined sugars are examples of sources for simple sugars. In situations where blood glucose levels are low, such as before a meal, insulin injections can help facilitate the uptake and storage of glucose from the bloodstream.