Cellular Communication and Metabolism: Energy Transformation Principles

This lecture covers the specificity of cellular communication and the coordination of cellular responses. Each cell has a unique set of proteins that allow it to respond differently to the same signal, such as adrenaline, which can trigger thermogenesis in brown adipose tissue and glycogen breakdown in the liver. The lecture explains the mechanisms of signal cessation and the importance of inactivation in cellular communication, highlighting diseases like cholera that result from signal interference. It introduces metabolism, defining it as the sum of biochemical reactions in an organism, and discusses metabolic pathways, including catabolic and anabolic processes. The principles of thermodynamics are applied to metabolism, explaining energy transformations and the concept of free energy. The lecture also details how ATP provides energy for cellular work by coupling exergonic and endergonic reactions, emphasizing the role of enzymes in accelerating metabolic reactions and the regulation of enzyme activity through allosteric mechanisms. Overall, the lecture integrates concepts of cellular signaling, metabolism, and energy management in biological systems.