4/9/25, 7:39
AM
PSYC 388 FINAL EXAM QUESTIONS AND ANDWERS WITH COMPLETE
SOLUTIONS VERIFIED LATEST UPDATE
Terms in this set (82)
Per gene expression in fruit flies peaked 6 hours before the PER protein rhythm,
What is the temporal relationship PER protein feeds-back to inhibit the activity of the per gene (transcription-
between per gene expression and PER translation negative feedback loop). PER and TIM proteins form dimers
protein levels in fruit flies? which return to the nucleus of the cell and turn off transcription of per and tim
genes - by interfering with CLOCK and CYC proteins
What is the temporal relationship PER and per are offset by about 6 h, consistent with the TTFL model. Light resets
between per gene expression and PER the loop by activating per genes trancsription (light exposure early in the night
protein levels in mammals? delays circadian time)
In fruit flies, on what clock gene or TIM protein levels rise at night and light degrades TIM. Degrading TIM late at
protein does light act to cause phase night sets TIM levels to later in the day - ie phase advance.
shifts, and how does light affect that gene Degrading TIM in the subjective day doesn't do anything
or protein?
In mice, on what clock gene or protein In mice, light acts on the Per1 and Per2 genes and proteins in the suprachiasmatic
does light act to cause phase shifts, and nucleus (SCN) to cause phase shifts
how does light affect that gene or
protein?
The circadian clock is said to be 'cell Tetrodotoxin on neurons eliminated action potential rhythms, when removed,
autonomous' - what does that mean, and rhythms returned at a phase predicted if the circadian oscillators had not been
what is the evidence? turned off
Is there a circadian clock in the The olfactory bulb has the most robust circadian rhythm clock discovered.
olfactory bulb? If so, does it cycle 'in The rhythms are in antiphase with the SCN (peaking in subjective day)
phase' with the SCN pacemaker (i.e.,
showing peaks
and troughs at the same time as the SCN).
Does it require the SCN circadian
pacemaker to cycle?
Bmal1 is essential for SCN clock cells to oscillate (Bmal1 KO mice are arrhythmic
Knockout of the gene Bmal1 has what
in constant conditions - cant sustain circadian rhythm)
effect on circadian rhythms in mice?
Bmal1 KO does not disable food anticipatory clock rhythms
Are there circadian clocks in peripheral Yes and they operate in a cell-autonomous manner but damp out in a few cycles
organs and tissues (e.g., liver, pancreas, (when disconnected)
etc) and if so, what stimuli are they
entrained by, and what role does the SCN
pacemaker play?
Why do circadian activity rhythms damp The single cells are still oscillating but if synchrony fails, there is no rhythm at
out in nocturnal rodents maintained in the population level and the clock function of the SCN is lost (disruption of
constant light for many weeks? What SCN
effect does constant light have on synchrony)
individual circadian clock cells in the Constant light reduces the amplitude of circadian gene expression rhythms in
SCN? SCN neurons: PER and CRY have disrupted feedback loops
PER protein forms a complex with CRY protein which inhibit the per and cry gene
In mice, what effect does Per protein
transcription that Bmal1-CLOCK performs.
have on Bmal1? Does it affect Bmal1 gene
Bmal1 gene expression is regulated by REV-ERBα and ROR proteins which repress
expression, or does it affect how
and activate Bmal1 transcription respectively; Per does not interact with his
Bmal1
feedback loop
protein activates the per and cry genes?
1/
7
, 4/9/25, 7:39
AM
If the SCN pacemaker is made up of Behaviour becomes arrhythmic or can experience splitting (2 sleep-wake cycles
several thousand individual circadian in a 24 h period)
clock cells, what happens to circadian
activity rhythms if those cells become
desynchronized from each other?
Ventrolateral part of SCN re entrained immediately.
Following a shift of the LD cycle,
Dorsolateral part re entrained gradually over 7 days.
do circadian clocks in different brain
SCN re entrains relatively quickly.
and
Peripheral clocks entrain more slowly due to being more strongly entrained to
body parts re-entrain at the same rate
food intake rather than LD cycles.
or at different rates?
What role do rods and cones play in Enhance sensitivity to light.
entrainment of the circadian clock by Expand wavelength range.
light in mammals? Are they necessary Redundancy with
(no ipRGCs.
entrainment without rods and cones)? Are
they sufficient (entrainment is possible
with only rods and cones)?
What role does the photopigment Melanopsin is necessary and sufficient photoreceptors for circadian entrainment.
melanopsin play in entrainment of the A small subset of ganglion cells (ipRGC) contain melanopsin and measure
circadian clock by light in mammals? Is ambient light levels
it necessary? Is it sufficient? What cells
in the retina contain melanopsin?
ipRGCs are directly photoreceptive, receive input from rods and cones, project to
What are 'intrinsically photoreceptive brain regions that mediate non-imaging forming responses to light, and are
retinal ganglion cells' and what is their critical for these responses.
relationship with rods and cones? ipRGCs respond to light indirectly by connections with rods and cones via
interneurons (bipolar cells)
Intrinsically photoreceptive retinal The wide-net like pattern of the ipRGCs measure ambient light levels and are
ganglion cells have many dendrites that useless at object discrimination (too broad receptive field)
form a wide net-like pattern. Form
determines function, and sometimes
we can infer what a neuron does
based on what it looks like. What does
the broad, net-like dendritic tree of
these neurons
imply about what these ganglion cells can
communicate about light. Would they
be useful for counting photons
(signalling
daytime) or would they have any use
for object recognition?
Which wavelength (and associated ipRGC have a peak sensitivity at 480 nm (blue light)
colour) of light is most effective for
inducing phase shifts?
The direct projection from the retina to The retinohypothalamic tract
the suprachiasmatic nucleus is called
the____________
In the mouse circadian clock, activation glutamate
of retinal photoreceptors by light
causes
release of which neurotransmitter in the
suprachiasmatic nucleus?
The neurotransmitter, glutamate, that is Glutamate is the photic neurotransmitter for shifting the SCN clock and
released in the SCN in response to light, mediates the SCN's response to light (conveys light input to SCN)
has what effect on SCN neurons?
2/
7
AM
PSYC 388 FINAL EXAM QUESTIONS AND ANDWERS WITH COMPLETE
SOLUTIONS VERIFIED LATEST UPDATE
Terms in this set (82)
Per gene expression in fruit flies peaked 6 hours before the PER protein rhythm,
What is the temporal relationship PER protein feeds-back to inhibit the activity of the per gene (transcription-
between per gene expression and PER translation negative feedback loop). PER and TIM proteins form dimers
protein levels in fruit flies? which return to the nucleus of the cell and turn off transcription of per and tim
genes - by interfering with CLOCK and CYC proteins
What is the temporal relationship PER and per are offset by about 6 h, consistent with the TTFL model. Light resets
between per gene expression and PER the loop by activating per genes trancsription (light exposure early in the night
protein levels in mammals? delays circadian time)
In fruit flies, on what clock gene or TIM protein levels rise at night and light degrades TIM. Degrading TIM late at
protein does light act to cause phase night sets TIM levels to later in the day - ie phase advance.
shifts, and how does light affect that gene Degrading TIM in the subjective day doesn't do anything
or protein?
In mice, on what clock gene or protein In mice, light acts on the Per1 and Per2 genes and proteins in the suprachiasmatic
does light act to cause phase shifts, and nucleus (SCN) to cause phase shifts
how does light affect that gene or
protein?
The circadian clock is said to be 'cell Tetrodotoxin on neurons eliminated action potential rhythms, when removed,
autonomous' - what does that mean, and rhythms returned at a phase predicted if the circadian oscillators had not been
what is the evidence? turned off
Is there a circadian clock in the The olfactory bulb has the most robust circadian rhythm clock discovered.
olfactory bulb? If so, does it cycle 'in The rhythms are in antiphase with the SCN (peaking in subjective day)
phase' with the SCN pacemaker (i.e.,
showing peaks
and troughs at the same time as the SCN).
Does it require the SCN circadian
pacemaker to cycle?
Bmal1 is essential for SCN clock cells to oscillate (Bmal1 KO mice are arrhythmic
Knockout of the gene Bmal1 has what
in constant conditions - cant sustain circadian rhythm)
effect on circadian rhythms in mice?
Bmal1 KO does not disable food anticipatory clock rhythms
Are there circadian clocks in peripheral Yes and they operate in a cell-autonomous manner but damp out in a few cycles
organs and tissues (e.g., liver, pancreas, (when disconnected)
etc) and if so, what stimuli are they
entrained by, and what role does the SCN
pacemaker play?
Why do circadian activity rhythms damp The single cells are still oscillating but if synchrony fails, there is no rhythm at
out in nocturnal rodents maintained in the population level and the clock function of the SCN is lost (disruption of
constant light for many weeks? What SCN
effect does constant light have on synchrony)
individual circadian clock cells in the Constant light reduces the amplitude of circadian gene expression rhythms in
SCN? SCN neurons: PER and CRY have disrupted feedback loops
PER protein forms a complex with CRY protein which inhibit the per and cry gene
In mice, what effect does Per protein
transcription that Bmal1-CLOCK performs.
have on Bmal1? Does it affect Bmal1 gene
Bmal1 gene expression is regulated by REV-ERBα and ROR proteins which repress
expression, or does it affect how
and activate Bmal1 transcription respectively; Per does not interact with his
Bmal1
feedback loop
protein activates the per and cry genes?
1/
7
, 4/9/25, 7:39
AM
If the SCN pacemaker is made up of Behaviour becomes arrhythmic or can experience splitting (2 sleep-wake cycles
several thousand individual circadian in a 24 h period)
clock cells, what happens to circadian
activity rhythms if those cells become
desynchronized from each other?
Ventrolateral part of SCN re entrained immediately.
Following a shift of the LD cycle,
Dorsolateral part re entrained gradually over 7 days.
do circadian clocks in different brain
SCN re entrains relatively quickly.
and
Peripheral clocks entrain more slowly due to being more strongly entrained to
body parts re-entrain at the same rate
food intake rather than LD cycles.
or at different rates?
What role do rods and cones play in Enhance sensitivity to light.
entrainment of the circadian clock by Expand wavelength range.
light in mammals? Are they necessary Redundancy with
(no ipRGCs.
entrainment without rods and cones)? Are
they sufficient (entrainment is possible
with only rods and cones)?
What role does the photopigment Melanopsin is necessary and sufficient photoreceptors for circadian entrainment.
melanopsin play in entrainment of the A small subset of ganglion cells (ipRGC) contain melanopsin and measure
circadian clock by light in mammals? Is ambient light levels
it necessary? Is it sufficient? What cells
in the retina contain melanopsin?
ipRGCs are directly photoreceptive, receive input from rods and cones, project to
What are 'intrinsically photoreceptive brain regions that mediate non-imaging forming responses to light, and are
retinal ganglion cells' and what is their critical for these responses.
relationship with rods and cones? ipRGCs respond to light indirectly by connections with rods and cones via
interneurons (bipolar cells)
Intrinsically photoreceptive retinal The wide-net like pattern of the ipRGCs measure ambient light levels and are
ganglion cells have many dendrites that useless at object discrimination (too broad receptive field)
form a wide net-like pattern. Form
determines function, and sometimes
we can infer what a neuron does
based on what it looks like. What does
the broad, net-like dendritic tree of
these neurons
imply about what these ganglion cells can
communicate about light. Would they
be useful for counting photons
(signalling
daytime) or would they have any use
for object recognition?
Which wavelength (and associated ipRGC have a peak sensitivity at 480 nm (blue light)
colour) of light is most effective for
inducing phase shifts?
The direct projection from the retina to The retinohypothalamic tract
the suprachiasmatic nucleus is called
the____________
In the mouse circadian clock, activation glutamate
of retinal photoreceptors by light
causes
release of which neurotransmitter in the
suprachiasmatic nucleus?
The neurotransmitter, glutamate, that is Glutamate is the photic neurotransmitter for shifting the SCN clock and
released in the SCN in response to light, mediates the SCN's response to light (conveys light input to SCN)
has what effect on SCN neurons?
2/
7
