Differentiate between glycogenesis and glycogenolysis

Hint: Glycogen is a multibranched polysaccharide of glucose that acts as an energy storage system in mammals, fungi, and bacteria. The polysaccharide structure is the primary source of glucose storage in the body. Glycogen is one of two types of energy sources, with glycogen being for short-term storage and triglyceride deposits in adipose tissue (i.e., body fat) being for long-term storage. Glycogen formation and breakdown are done by the process of glycogenesis and glycogenolysis.

Complete answer:
Glycogen is mainly produced and processed in the cells of the liver and skeletal muscle in humans. Glycogen can account for 5–6% of the fresh weight of the liver, and an adult liver weighing 1.5 kg can store about 100–120 grams of glycogen. Glycogen is present in skeletal muscle at a low concentration (1–2 percent of muscle mass), and an adult weighing 70 kg stores approximately 400 grams of glycogen.


Note: Human blood contains approximately 4 grams of glucose at all times; in fasting individuals, blood glucose is kept constant at this level at the expense of glycogen stores in the liver and skeletal muscle.
- Glycogen reserves in skeletal muscle act as a source of energy storage for the muscle; nevertheless, muscle glycogen degradation inhibits muscle glucose intake from the blood, raising the volume of blood glucose available for use of other tissues.
- The glycogen stores in the liver serve as a source of glucose for use throughout the body, especially the central nervous system.
- Glycogenolysis, in particular, is essential in the adrenaline-induced fight-or-flight reaction and the control of blood glucose levels.