Sciences_week_11_Glycogen Met. (2).pdf

GLYCOGEN METABOLISM GLYCOGENOLYSIS AND GLYCOGENESIS  THE MAJOR PATHWAYS OF CARBOHYDRATE METABOLISM BEGIN OR END WITH GLUCOSE Utilization of Glucose as a source of energy (Glycolysis) Gluconeogenesis from non-carbohydrate precurspors Storage of Glucose as Glycogen (Glycogenesis)...

GLYCOGEN METABOLISM GLYCOGENOLYSIS AND GLYCOGENESIS  THE MAJOR PATHWAYS OF CARBOHYDRATE METABOLISM BEGIN OR END WITH GLUCOSE Utilization of Glucose as a source of energy (Glycolysis) Gluconeogenesis from non-carbohydrate precurspors Storage of Glucose as Glycogen (Glycogenesis) Release of Glucose from Glycogen (Glycogenolysis) Pentose Phosphate Pathway for production of NADPH  OVERVIEW Glycogen is the major storage carbohydrate in animals, corresponding to starch in plants. it is a branched polymer of α-D-glucose. It occurs mainly in liver and muscle, with modest amounts in the brain. Glycogen synthesis and degradation are the essential pathways of energy metabolism. GLYCOGENOLYSIS GLYCOGENESIS These are a group of genetic diseases that result from a defect in an enzyme required for glycogen synthesis or degradation. They result either in formation of glycogen that has an abnormal structure, or in the accumulation of excessive amounts of normal glycogen in specific tissues as a result of impaired degradation. A particular enzyme may be defective in a single tissue, such as liver (resulting in hypoglycemia) or muscle (muscle weakness), or the defect may be more generalized, affecting liver, muscle, kidney, intestine, and myocardium. The severity of the glycogen storage diseases (GSDs) ranges from fatal in infancy to mild disorders that are not life threatening.