Physiological Role of Oxidative Stress and Antioxidant Systems in Normal Cellular Functions

<jats:p>Oxidative stress represents a fundamental feature of cellular metabolism and is characterized by a dynamic balance between the generation of reactive oxygen and nitrogen species and their neutralization. Under physiological conditions, these processes play a crucial role in intracellular signaling, regulation of gene expression, and adaptive mechanisms. However, excessive production of oxidative molecules leads to structural and functional damage of biomacromolecules. The present study provides a systematic analysis of the molecular basis of oxidative stress, its impact on cellular functions, and the integrative role of antioxidant defense systems, based on contemporary scientific evidence.</jats:p>