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PSYC 388 Questions and Verified Answers
Q: Phase
ANS: - a point within the cycle
- the instantaneous state of the clock
- a position within its cycle
** can refer to range of phases (daily active phase or rest phase)
Q:
Period (tau)
ANS: - duration of a complete cycle
Q:
Wavelength (lambda)
ANS: - distance between two acrophases (peaks)
- distance a wave travels in one period, or length of one cycle
Q:
Amplitude (2 definitions)
ANS: - the range (peak to trough) OR
- half the range (peak to mean/mesor)
Q:
Acrophase
ANS: the peak of the curve (sine wave)
Q:
What are the four 'circa' rhythms? (and give examples)
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ANS: 1. Circaannual (approx. 1 year)
Ex: summer and winter
2. Circalunar (approx 29.5 days)
Ex: determines how much light there is at night
3. Circadian (approx. 24hrs)
4. Circatidal (approx. 12.5 hrs)
Ex: high and low tide
Q:
What two characteristics distinguish these from
other rhythms?
ANS: 1. the duration of each cycle (its period), matches a major geophysical cycle
2. the rhythms PERSIST in the absence of environmental cycles, with a periodicity
that only approximates the geophysical cycle
Q:
How do you test experimentally whether a daily rest-activity rhythm in an animal is
generated by an internal circadian clock, and not by environmental cycles?
ANS: - keep the animal in constant conditions attempting to remove all rhythmic
stimuli
Q:
Is the circadian rhythm depicted in this actogram free-running faster or slower than
24h?
ANS: - staircase <<24hrs
- upside-down staircase >>24hrs
Q:
What is meant by temperature compensation, and why is this a necessary
characteristic of a circadian clock?
PSYC 388 Questions and Verified Answers
Q: Phase
ANS: - a point within the cycle
- the instantaneous state of the clock
- a position within its cycle
** can refer to range of phases (daily active phase or rest phase)
Q:
Period (tau)
ANS: - duration of a complete cycle
Q:
Wavelength (lambda)
ANS: - distance between two acrophases (peaks)
- distance a wave travels in one period, or length of one cycle
Q:
Amplitude (2 definitions)
ANS: - the range (peak to trough) OR
- half the range (peak to mean/mesor)
Q:
Acrophase
ANS: the peak of the curve (sine wave)
Q:
What are the four 'circa' rhythms? (and give examples)
, Page | 2
ANS: 1. Circaannual (approx. 1 year)
Ex: summer and winter
2. Circalunar (approx 29.5 days)
Ex: determines how much light there is at night
3. Circadian (approx. 24hrs)
4. Circatidal (approx. 12.5 hrs)
Ex: high and low tide
Q:
What two characteristics distinguish these from
other rhythms?
ANS: 1. the duration of each cycle (its period), matches a major geophysical cycle
2. the rhythms PERSIST in the absence of environmental cycles, with a periodicity
that only approximates the geophysical cycle
Q:
How do you test experimentally whether a daily rest-activity rhythm in an animal is
generated by an internal circadian clock, and not by environmental cycles?
ANS: - keep the animal in constant conditions attempting to remove all rhythmic
stimuli
Q:
Is the circadian rhythm depicted in this actogram free-running faster or slower than
24h?
ANS: - staircase <<24hrs
- upside-down staircase >>24hrs
Q:
What is meant by temperature compensation, and why is this a necessary
characteristic of a circadian clock?
