The article discusses the molecular components of the mammalian circadian clock, focusing on how mammals synchronize their circadian activity with environmental light and darkness. The suprachiasmatic nucleus (SCN) in the hypothalamus acts as the master circadian clock, receiving light signals from the eyes and synchronizing peripheral clocks throughout the body. These peripheral clocks are influenced by humoral signals, metabolic factors, and body temperature. At the molecular level, the clock involves a transcriptional feedback oscillator, where CLOCK and BMAL1 proteins initiate the transcription of genes that eventually inhibit their own activity. Other molecular oscillators can operate independently of this transcription-based clock. The circadian clock regulates various physiological processes, including body temperature, blood pressure, and metabolism, and disruptions in these clocks can lead to diseases such as sleep disorders and metabolic issues. The article also highlights the role of temperature compensation, ensuring the clock's stability across different temperatures, and the importance of the SCN as a master synchronizer, coordinating the circadian rhythms of various tissues. The study emphasizes the complexity of the circadian system, involving both transcriptional and non-transcriptional mechanisms, and the potential for therapeutic applications in treating circadian-related disorders.The article discusses the molecular components of the mammalian circadian clock, focusing on how mammals synchronize their circadian activity with environmental light and darkness. The suprachiasmatic nucleus (SCN) in the hypothalamus acts as the master circadian clock, receiving light signals from the eyes and synchronizing peripheral clocks throughout the body. These peripheral clocks are influenced by humoral signals, metabolic factors, and body temperature. At the molecular level, the clock involves a transcriptional feedback oscillator, where CLOCK and BMAL1 proteins initiate the transcription of genes that eventually inhibit their own activity. Other molecular oscillators can operate independently of this transcription-based clock. The circadian clock regulates various physiological processes, including body temperature, blood pressure, and metabolism, and disruptions in these clocks can lead to diseases such as sleep disorders and metabolic issues. The article also highlights the role of temperature compensation, ensuring the clock's stability across different temperatures, and the importance of the SCN as a master synchronizer, coordinating the circadian rhythms of various tissues. The study emphasizes the complexity of the circadian system, involving both transcriptional and non-transcriptional mechanisms, and the potential for therapeutic applications in treating circadian-related disorders.