Carbohydrates, Glucose and Glycogen
Carbohydrates, also known as carbs, are essential nutrients that provide energy to the body.
Glucose is the molecule resulting from the digestion of carbohydrates.
Glucose is a simple carbohydrate molecule and the main source of energy for our body's cells. It is found in various foods, such as fruits, honey, and is also produced by our liver. Glucose circulates in the blood and is regulated by the hormone insulin.
When not immediately used to produce energy, it is stored as a reserve in the liver, muscles, and kidneys, in the form of glycogen, for later use when the body needs it.
It is a short-term energy reserve and is broken down into glucose when necessary.
The reserve of glycogen in skeletal muscle is used for its own needs, while the glycogen stored in the liver is mainly used to maintain blood glucose levels.
This process called glycogen synthesis, also known as glycogenesis, is the process by which the cells of the liver and muscles synthesize glycogen from the available glucose in the body. This process occurs when there is an excess of glucose in the bloodstream, usually after a carbohydrate-rich meal.
When blood glucose levels increase, the pancreas releases the hormone insulin. Insulin acts as a signaling molecule for the cells of the liver and muscles, stimulating glucose absorption from the bloodstream and converting this excess glucose into glycogen, thereby reducing blood glucose levels.
Glycogen synthase is the key enzyme responsible for catalyzing the synthesis of glycogen.
It joins individual glucose molecules and links them together, forming a long chain of glucose, which is the structure of glycogen. In this way, glycogen is stored in hepatic cells (liver) and muscle cells as a form of energy reserve.
When blood glucose levels decrease, there is an increase in the secretion of the hormone glucagon, whose main function is to signal the release of glucose into the bloodstream, derived from the degradation of hepatic glycogen (stored). This process of glucose degradation is a metabolic process known as glycolysis through the enzyme responsible for glycogen phosphorylase. This process is essential for the production of energy in cells, providing the necessary ATP for various cellular activities.
