Glucose homeostasis is a critical physiological process that ensures a constant supply of energy to cells. The molecular basis of this regulation primarily involves two opposing metabolic pathways: glycolysis and gluconeogenesis. Glycolysis is responsible for the breakdown of glucose to generate energy in the form of ATP, whereas gluconeogenesis synthesizes glucose from non-carbohydrate precursors, particularly during fasting conditions.This article aims to analyze the key molecular mechanisms underlying these pathways, with a focus on enzyme activity, regulatory factors, and hormonal control. Special attention is given to rate-limiting enzymes such as phosphofructokinase-1, pyruvate kinase, and fructose-1,6-bisphosphatase, as well as the role of allosteric effectors and covalent modifications. The findings demonstrate that the coordinated regulation of glycolysis and gluconeogenesis is essential for maintaining metabolic balance and preventing energy inefficiency. Hormones such as insulin and glucagon play a central role in modulating these pathways. Disruptions in this regulation are closely associated with metabolic disorders, including diabetes mellitus. In conclusion, understanding the molecular mechanisms of glucose metabolism provides valuable insights into both normal physiology and disease pathogenesis, highlighting potential targets for therapeutic intervention.