• Akshay Pawar
• Daljeet Singh Dhanjal
• Chirag Chopra
• Reena Singh

Circadian rhythm is the mechanism of the diurnal cycle and the response of the body towards the intensity of light and temperature on daily activities, excluding the effect of environmental stimuli. The circadian rhythm has a direct impact on the life of all living organisms, which might be diurnal or biennial. Still, all of these organisms exhibit molecular or metabolic processes that function under the effect of light, temperature, day and night and even seasons. Different model organisms have been used for studying the circadian functioning or system by various researchers, for example; within fungi, Neurospora was used, in prokaryotes, Cyanobacteria were used while among insects Drosophila and in mammals, mouse was taken as a study model. Later on, plants were also studied to explain the circadian rhythms under the effect of light and temperature, and the researchers chose the light-harvesting complex as the primary source of their study. Along with the external factors like light and temperature, the intrinsic study of genes and proteins is also well stated. In these studies, different genes showed their presence by generating the proteins that will increase or decrease according to temperature and provide the information of day and night timing after every 24 hours. This showed the molecular basis of the biological clock. The malfunctioning of the body due to metabolic changes leads to various disorders such as diabetes, obesity, hypertension, the cardiovascular disease which can arise due to lack of REM-sleep, workload, travel stress, jet lag and sometimes can even be fatal. This review intends to highlight the mechanism of the biological clock, the effect of the external environment on biological clock and genetics of circadian rhythm. Moreover, it will also discuss the association of metabolic disorders with circadian rhythms and assessment of the different model organisms to understand the circadian rhythm.

Circadian, light, temperature, biological clock, model, genes, malfunctioning

"MOLECULAR BASIS OF BIOLOGICAL CLOCKS AND CIRCADIAN RHYTHMS", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.5, Issue 12, page no.475-482, December 2018, Available :http://www.jetir.org/papers/JETIRDT06062.pdf

"MOLECULAR BASIS OF BIOLOGICAL CLOCKS AND CIRCADIAN RHYTHMS", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.5, Issue 12, page no. pp475-482, December 2018, Available at : http://www.jetir.org/papers/JETIRDT06062.pdf