Cellular stress refers to the response of cells to environmental or internal stresses that disrupt cellular homeostasis, leading to potential damage or dysfunction. This can include factors like heat shock, nutrient deprivation, oxygen deprivation, or exposure to toxins. The cellular stress response involves various cellular pathways and mechanisms, such as the activation of stress-responsive proteins, DNA repair, cell cycle arrest, and apoptosis. Understanding how cells respond to stress can provide insights into diseases like cancer, neurodegenerative disorders, and metabolic disorders, as well as potential therapeutic targets for intervention.