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10 Cards in this Set

  • Front
  • Back
circadian rythm
about a day
free-running vs. entraining the rythm
free running - clock shifts to the right
entraining the clock - locks back on to natural biological clock again
*doesn't repsond to external cues
free run - absense of external cues and the clock still goes
entrain - lock onto specific time
-zeitgeber - cue that entrains
-temp insensitivity - not dependent upon temperature
how do most animals best free-run?
in total darkness
Where is the clock?
mammals - SCN
fish/reptiles - pineal gland
insects - brain
communicates via hormones, doesn't have to be connected
Period Genes:
per(+) -> wild-type(24 hr)
per(s) -> period short(9hr)
per(Li) -> period long (29 hr)
per(o) -> no period(random)
Explain Jet Lag
SCN adjusts in one day but there's a seperate clock in lungs/liver/muscle that takes longer to adjust. one solution: start eating on destination time days in advance
transcriptional clock
genetic clock that relies on DNA transcription. Period protein shuts off period gene over a 24-hr. rythym
-doubletime breaks down per. protein
-cryptochrome activated by the sun and detroys per/tim dimers
circannual rythm
an annual rythym. when isolate organism, rythym drifts to the left