Glycolysis

Contents in brief: What is glycolysis? Glycolysis: the first metabolic pathway to be elucidated Why is glycolysis so important? The steps of glycolysis Reaction 1: glucose phosphorylation to glucose 6-phosphate The importance of glucose phosphorylation Other possible fates of glucose 6-phosphate Reaction 2: isomerization of glucose 6-phosphate to fructose 6-phosphate Reaction 3: phosphorylation of fructose […]

Glycogen: an efficient storage form of energy in aerobic conditions

What is the net energy yield for the oxidation of a glucose unit from glycogen in aerobic conditions? In aerobic conditions, the oxidation of a free glucose to CO2 and H2O (glycolysis, Krebs cycle and oxidative phosphorylation) leads to the net production of about 30 molecules of ATP. Glucose from the action of glycogen phosphorylase: glucose-1-phosphate […]

Carbohydrate ingestion 60 min before exercise

Introductory statement An high-carbohydrate diet in the days before exercise, as well as ingestion of meals high in carbohydrate 3-4 h before exercise, better if with low glycemic index, can have positive effects on athlete’s performance. For many years it has been suggested that ingestion of carbohydrates 30-60 min before exercise may adversely affect performance because […]

Glycogen: an efficient storage form of energy in anaerobic conditions

What is the net energy yield for the oxidation of a glucose unit from glycogen in anaerobic conditions? In anaerobic conditions, the oxidation of a free glucose to lactate leads to the net production of two molecules of ATP. Glucose from the action of glycogen phosphorylase: glucose-1-phosphate release (about 90% of the removed units) Glycogen […]

Blood glucose levels and liver

Blood glucose levels and hepatic glycogen One of the main functions of the liver is to participate in the maintaining of blood glucose levels within well defined range (in the healthy state before meals 60-100 mg/dL or 3.33-5.56 mmol/L). To do it the liver releases glucose into the bloodstream in: fasting state; between meals; during physical […]

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