Question 1

Release of melatonin is suppressed by
A) exposure of the animal to light.
B) exposure of the animal to darkness.
C) input from peripheral clocks.
D) input from the superior colliculi.

Accepted Answer

Melatonin is a hormone that is released in response to darkness and suppressed by exposure to light. Therefore, option A is the correct answer, as it states that melatonin release is suppressed by exposure to light. Options B, C, and D are incorrect, as they do not accurately describe the regulation of melatonin release.

Question 2

The SCN is active during the
A) day for diurnal species and during the night for nocturnal species.
B) day for nocturnal species and during the night for diurnal species.
C) day for both diurnal and nocturnal species.
D) night for both diurnal and nocturnal species.

Accepted Answer

The Suprachiasmatic Nucleus (SCN) acts as the primary circadian clock in mammals, regulating sleep-wake cycles and other rhythmic physiological functions. It is active during the day for both diurnal (day-active) and nocturnal (night-active) species, as it responds to light signals to synchronize the body's internal clock with the external environment.

Question 3

Courtney believes that pulling regular "all-nighters" is an important part of being a college student, and she frequently goes all night without any sleep at all. Given what you know about sleep cycles and sleep deprivation, what else can you assume about Courtney?
A) She probably is just one of those people who don't need much sleep.
B) She is a conscientious student who probably has a very high grade-point average
C) She probably has a lower grade point average than most of her classmates and often feels depressed.
D) She has probably maintained this same pattern of sleeping since childhood.

Accepted Answer

The question states that Courtney believes pulling all-nighters is an important part of being a college student, which suggests that she may not have good study habits and time-management skills. Pulling all-nighters can lead to sleep deprivation, which has negative effects on cognitive function and mood. Therefore, it is likely that Courtney has a lower grade point average than most of her classmates and often feels depressed.

Question 4

Stephanie, who lives in California, is preparing to compete in track and field at the Olympics in London. She plans to arrive in London
A) two weeks before competing, because her peripheral clocks in her muscles and lungs take longer than her SCN to adjust to a new time zone.
B) two weeks before competing, because her SCN requires this time in order to adjust to the new time zone.
C) a couple of days before competing, because her SCN and peripheral clocks only require a short time to adjust to the new time zone.
D) a couple of days before competing, because eastern travel is easier on her SCN and peripheral clocks than the western travel she experienced competing in Beijing.

Accepted Answer

It takes longer for peripheral clocks in muscles and lungs to adjust to a new time zone than the SCN, which regulates the master clock in the brain. As Stephanie is preparing to compete in track and field, she needs to ensure that all her peripheral clocks are fully synchronized with her master clock to optimize her performance. Hence, she should arrive in London two weeks before competing, as it takes time for the peripheral clocks to adjust to a new time zone.

Question 5

Who is MOST likely to be experiencing major depressive disorder with seasonal pattern?
A) Margaretta who lives at the equator in a town currently experiencing summer
B) Nella who lives at the equator in a town currently experiencing winter
C) Beckie who lives at higher latitudes in a town currently experiencing summer
D) Yuki who lives at higher latitudes in a town currently experiencing winter

Accepted Answer

Major depressive disorder with seasonal pattern (also known as seasonal affective disorder) typically occurs in people who live at higher latitudes and experience reduced sunlight during the winter months. Therefore, Yuki who lives at higher latitudes in a town currently experiencing winter is the most likely to be experiencing this disorder.

Question 6

Which of the following is an accurate description of the effects of zeitgebers on the body's internal clocks?
A) Both the SCN and peripheral clocks are affected more by light than any other type of zeitgeber.
B) The SCN is more affected by light, whereas the peripheral clocks are more affected by feeding patterns.
C) The peripheral clocks are more affected by light, whereas the SCN is more affected by physical activity.
D) Both the SCN and peripheral clocks are affected more by physical activity and feeding patterns than by light.

Accepted Answer

The SCN is primarily regulated by light and is therefore more affected by it than peripheral clocks. However, peripheral clocks are more affected by feeding patterns than light.

Question 7

If SCN tissue is transplanted from a short-period hamster into a normal hamster,
A) no change can be observed.
B) the normal hamster will show 20-hour cycles.
C) the normal hamster will show 24-hour cycles.
D) the normal hamster will show 25-hour cycles.

Accepted Answer

The SCN (suprachiasmatic nucleus) is responsible for controlling circadian rhythms in mammals. When SCN tissue from a short-period hamster (which has a circadian rhythm shorter than 24 hours) is transplanted into a normal hamster, the recipient's circadian rhythm will adjust to match that of the donor's, hence showing 20-hour cycles.

Question 8

Jessica just watched an extremely scary video with her friends and is now finding it very difficult to get to sleep, even though she knows that she is very tired. It is most likely that Jessica's sleeplessness is related to increases in the release of
A) melatonin.
B) cortisol.
C) dopamine.
D) acetylcholine.

Accepted Answer

Cortisol is a hormone that is released in response to stress, and watching a scary video can certainly be a stressful experience. Elevated levels of cortisol can interfere with sleep and lead to difficulty falling or staying asleep. Melatonin is a hormone that helps regulate sleep-wake cycles and increase at night to promote sleep, so it's unlikely to be the cause of Jessica's sleeplessness. Dopamine and acetylcholine are neurotransmitters that can affect sleep to some extent, but cortisol is more likely to be the primary factor in this scenario.

Question 9

In fruit flies, per and tim proteins
A) inhibit the Clock protein.
B) promote the production of the Clock protein.
C) are inhibited by the Clock protein.
D) inhibit the production of each other and the Clock protein.

Accepted Answer

Per and tim proteins inhibit the Clock protein by binding to it and preventing it from activating transcription of the clock genes.

Question 10

Great Aunt Mary has always been a "lark," getting up early, working busily during the day, and then going to bed relatively early. She recently had a slight stroke, and the only thing that seems different about her is that her normal periods of sleeping and waking have changed. Now, you never know when she will get up or when she will go to bed, and she is often up half the night but sleeping during the day. Given what you have learned about sleep and waking, which one of the following brain areas might have been affected by her stroke?
A) the rubrospinal tract
B) the retinohypothalamic pathway
C) the mesolimbicstriatal pathway
D) the thalamopituitary pathway

Accepted Answer

The retinohypothalamic pathway connects the eyes to the suprachiasmatic nucleus in the hypothalamus, which helps regulate the sleep-wake cycle. If this pathway is damaged, it can disrupt the timing of sleep and wakefulness. Since the only change in behavior noted in Great Aunt Mary is a disruption in her sleep-wake cycle, the retinohypothalamic pathway is the most likely brain area that was affected by her stroke.

Question 11

Melatonin is secreted by the
A) superior colliculi.
B) SCN.
C) the pituitary gland.
D) the pineal gland.

Accepted Answer

Melatonin is primarily secreted by the pineal gland, which is located in the brain. The other options, such as the superior colliculi and the pituitary gland, are not directly involved in melatonin secretion. The SCN (Suprachiasmatic nucleus) is located in the hypothalamus and plays a key role in regulating the circadian rhythm, which affects melatonin secretion, but it is not the direct source of melatonin secretion.

Question 12

Marleen was surprised to learn that melatonin was released during the _____ in diurnal species and during the _____ in nocturnal species.
A) day; night
B) night; day
C) day; day
D) night; night

Accepted Answer

The answer of  Marleen was surprised to learn that melatonin...

Question 13

The origin of the SCN's rhythms may be
A) exposure to the mother's rhythms in utero.
B) input from the retinohypothalamic tract.
C) exposure to melatonin.
D) oscillations of protein production and degradation.

Accepted Answer

The SCN's rhythms originate from intrinsic oscillations of protein production and degradation within its neurons, which form the basis of the circadian clock.

Question 14

Cortisol levels are normally
A) highest in the morning.
B) highest midday.
C) highest in the evening.
D) stable throughout the day.

Accepted Answer

Cortisol levels naturally peak in the morning and gradually decrease throughout the day, with the lowest levels typically occurring in the evening. This is known as the diurnal rhythm of cortisol secretion.

Question 15

Rolanda is studying for a quiz. She knows that #1 in this diagram is pointing to the

A) SCN.
B) preoptic area (POA).
C) optic chiasm.
D) LGN of the thalamus.

Accepted Answer

The answer of Rolanda is studying for a quiz. She...

Question 16

As per and tim proteins degrade over time,
A) the Clock protein is inhibited, leading to greater production of per and tim.
B) the Clock protein is activated, leading to greater production of per and tim.
C) more melatonin is released by the pineal gland, leading to greater production of per and tim.
D) the SCN is inhibited, leading to less production of per and tim.

Accepted Answer

The Clock protein, along with Cycle, activates the transcription of per and tim genes. As PER and TIM proteins degrade, this reduces their inhibition on the Clock-Cycle complex, leading to its activation and thus greater production of PER and TIM proteins, maintaining the circadian rhythm cycle.

Question 17

In fruit flies, levels of the proteins per and tim are highest during which of the stages illustrated in this figure?

A) number 1
B) number 2
C) number 3
D) number 4

Accepted Answer

The answer of  In fruit flies, levels of the proteins...

Question 18

John travels frequently to distant parts of the globe. He believes that adjusting his mealtimes to the destination time zone is helpful in dealing with jet lag. After studying the material in your textbook, you tell John that
A) he's wasting his time, as adjusting his mealtimes will have little if any effect on jet lag.
B) he should expect some benefits, as his SCN is very responsive to changes in feeding patterns.
C) he should expect some benefits, as his peripheral clocks should respond to changes in feeding patterns.
D) this is a highly effective strategy, because both his SCN and peripheral clocks are highly sensitive to changes in feeding patterns.

Accepted Answer

John should expect some benefits as his peripheral clocks should respond to changes in feeding patterns. While adjusting meal times may not have a significant effect on the master clock (SCN) in the brain, peripheral clocks in other parts of the body can adjust more readily to changes in feeding patterns, helping to manage some symptoms of jet lag.

Question 19

A blood clot recently formed in the SCN of Sam's hypothalamus. Fortunately, the clot was contained, and he seems to be doing very well. However, there has been a change in his behavior. What might you expect that change to be?
A) He has problems remembering names and faces.
B) His vision is slightly blurred all the time.
C) He seems to have problems with going to sleep and waking up at normal times.
D) His muscular coordination is not as good as it used to be.

Accepted Answer

The SCN (suprachiasmatic nucleus) is responsible for regulating the body's circadian rhythm, which controls the sleep-wake cycle. A blood clot in the SCN could disrupt the body's ability to regulate this rhythm, resulting in problems with going to sleep and waking up at normal times. This would cause a change in behavior, making option C the best answer.

Question 20

The stress of crossing multiple time zones during air travel may
A) increase the release of melatonin.
B) decrease the release of melatonin.
C) increase the release of cortisol.
D) decrease the release of cortisol.

Accepted Answer

Stressful events, such as crossing multiple time zones during air travel, can increase the release of cortisol, a hormone that helps the body cope with stress.

Quiz 11: Sleep and Waking

Release of melatonin is suppressed by

The SCN is active during the

Courtney believes that pulling regular "all-nighters" is an important part of being a college student, and she frequently goes all night without any sleep at all. Given what you know about sleep cycles and sleep deprivation, what else can you assume about Courtney?

Stephanie, who lives in California, is preparing to compete in track and field at the Olympics in London. She plans to arrive in London

Who is MOST likely to be experiencing major depressive disorder with seasonal pattern?

Which of the following is an accurate description of the effects of zeitgebers on the body's internal clocks?

If SCN tissue is transplanted from a short-period hamster into a normal hamster,

Jessica just watched an extremely scary video with her friends and is now finding it very difficult to get to sleep, even though she knows that she is very tired. It is most likely that Jessica's sleeplessness is related to increases in the release of

In fruit flies, per and tim proteins

Melatonin is secreted by the

Marleen was surprised to learn that melatonin was released during the _ in diurnal species and during the _ in nocturnal species.

The origin of the SCN's rhythms may be

Cortisol levels are normally

Rolanda is studying for a quiz. She knows that #1 in this diagram is pointing to the

As per and tim proteins degrade over time,

In fruit flies, levels of the proteins per and tim are highest during which of the stages illustrated in this figure?

John travels frequently to distant parts of the globe. He believes that adjusting his mealtimes to the destination time zone is helpful in dealing with jet lag. After studying the material in your textbook, you tell John that

A blood clot recently formed in the SCN of Sam's hypothalamus. Fortunately, the clot was contained, and he seems to be doing very well. However, there has been a change in his behavior. What might you expect that change to be?

The stress of crossing multiple time zones during air travel may