Biology 1002B Lecture Notes - Circadian Rhythm, Northern Blot, Suprachiasmatic Nucleus
21 Apr 2013
School
Department
Course
Professor
Document Summary
Clock set/reset by external environment astronomical time: clock not totally independent of environment and entrain to external light. If environment is constant, the clock still works (free running: body temperature and hormone secretion in circadian rhythm even in constant darkness. Northern blot of mrna transcript abundance shows that photosynthetic gene is expressed in dark: not only a response to light because it is a circadian rhythm (anticipates light, ways to distinguish circadian from non-circadian diurnal rhythms. Photosynthesis the process is not circadian (needs sunlight) Dna replication has circadian rhythm but why does it tend to occur at night: evidence that circadian clocks are genetic. E. g. eclosion mutants show period identified by peaks is either shorter or longer (no constant rhythm: mechanism of oscillating gene expression in neurospora biological clock (frq expression) Every living thing have clocks and neurospora has frq clock gene: the change in transcription and translation of frq gene is what oscillates/ keeping time in clock.
