Bio 8

Question 1

1. Which of the following best describes an endogenous circannual rhythm?
   A) A yearly rhythm regulated purely by environmental temperature.
   B) A self-generated rhythm that prepares an animal for seasonal changes.
   C) A daily rhythm that depends on external light-dark cues.
   D) A behavioral response triggered immediately by environmental stimuli.

Answer 1

Answer: B
Explanation: Endogenous circannual rhythms are internally generated rhythms that occur yearly and help animals prepare for seasonal changes, even without direct environmental cues.

Question 2

Which of the following is the strongest zeitgeber for land animals?
A) Meals
B) Exercise
C) Social interaction
D) Light

Answer 2

Answer: D
Explanation: Light is the most powerful zeitgeber (“time-giver”) that resets circadian rhythms in land animals.

Question 3

Which evidence suggests a biological basis for mood rhythms?
A) People feel happiest at random times during sleep deprivation studies.
B) Mood improves throughout the day regardless of light and temperature changes.
C) People have no consistent mood changes throughout the day.
D) Mood depends solely on sleep duration.

Answer 3

Answer: B
Explanation: Studies showed that even under constant conditions, people still experience peak mood in the late afternoon, suggesting an internal circadian rhythm for emotional well-being.

Question 4

What happens to circadian rhythms in people living in constant darkness, such as submariners or Antarctic workers?
A) They maintain an exact 24-hour rhythm indefinitely.
B) Their rhythms gradually drift out of sync without light cues.
C) They easily adjust to artificial light cues.
D) Their rhythms shorten to exactly 18 hours.

Answer 4

Answer: B
Explanation: Without external light cues, circadian rhythms tend to drift, and maintaining synchronization becomes difficult.

Question 5

What pattern was found when comparing sleep midpoints in eastern vs. western Germany?
A) No difference because of the unified time zone.
B) People in the east had later sleep midpoints.
C) People in the west had later sleep midpoints.
D) Sleep patterns were completely random.

Answer 5

Answer: C
Explanation: Even with the same clock time, western Germans had later sleep midpoints because sunrise occurs later there.

Question 6

Which statement is TRUE regarding blind individuals and circadian rhythms?
A) All blind people use noise and meals to perfectly synchronize rhythms.
B) Most blind individuals have shorter than 24-hour rhythms.
C) Some blind people experience free-running rhythms that drift from 24 hours.
D) Blind individuals rely solely on gravitational cues for rhythm setting.

Answer 6

Answer: C
Explanation: Some blind people experience free-running rhythms that drift without strong light-based zeitgebers.

Question 7

Which of the following best explains why adjusting to westward travel is generally easier than eastward travel?

A) Traveling west involves a phase advance, which is easier to achieve.
B) Traveling west requires a phase delay, aligning better with staying awake later.
C) Traveling west avoids disruption of the suprachiasmatic nucleus (SCN).
D) Traveling west suppresses cortisol production, reducing stress.

Answer 7

Answer: B) Traveling west requires a phase delay, aligning better with staying awake later.

Brief Explanation:
Traveling west means delaying the internal clock (staying up later and waking later), which is easier than advancing it (going to bed earlier) as needed when traveling east.

Question 8

Which of the following is NOT a recommended strategy to help night-shift workers adjust their circadian rhythms?

A) Sleeping in a very dark room during the day.
B) Working under bright, bluish lights at night.
C) Exposing oneself to natural sunlight immediately after a night shift.
D) Using artificial lighting with intensity comparable to noon sunlight at night.

Answer 8

Answer: C) Exposing oneself to natural sunlight immediately after a night shift.

Brief Explanation:
Exposure to sunlight after a night shift would reinforce daytime rhythms, not help adjust to a night schedule. Night workers need darkness during the day and bright lights at night to shift their rhythms.

Question 9

MCQ 3:

Damage to the suprachiasmatic nucleus (SCN) would most likely result in:

A) Total loss of sleep ability.
B) Random, disorganized sleep-wake patterns.
C) Permanent insomnia with intact body temperature rhythms.
D) Shortened circadian cycles to about 20 hours.

Answer 9

Answer: B) Random, disorganized sleep-wake patterns.

Brief Explanation:
The SCN is the brain’s master clock. Damage to it disrupts coherent circadian rhythms, leading to irregular or random patterns of sleep and temperature regulation, rather than loss of sleep altogether or a simple shortening of the rhythm.

Question 10

Which type of retinal cells directly reset the suprachiasmatic nucleus (SCN) in response to light, even in the absence of rods and cones?

A) Horizontal cells
B) Amacrine cells
C) Specialized ganglion cells containing melanopsin
D) Bipolar cells

Answer 10

Answer: C) Specialized ganglion cells containing melanopsin
Explanation: These special ganglion cells detect light directly using melanopsin and send signals via the retinohypothalamic path to reset the SCN.

Question 11

Why are blind mole rats still able to synchronize their circadian rhythms with the light-dark cycle?

A) They have highly sensitive rods and cones
B) They use olfactory cues instead of visual cues
C) They possess light-sensitive ganglion cells independent of rods and cones
D) They rely entirely on the Earth’s magnetic field

Answer 11

Answer: C) They possess light-sensitive ganglion cells independent of rods and cones
Explanation: Even without functional eyes, mole rats reset circadian rhythms using melanopsin-containing ganglion cells.

Question 12

What characteristic of the special ganglion cells makes them particularly suited for regulating circadian rhythms?

A) They rapidly respond to momentary changes in light
B) They are most sensitive to red light wavelengths
C) They respond slowly to light and reflect overall light intensity
D) They are located exclusively in the occipital lobe

Answer 12

Answer: C) They respond slowly to light and reflect overall light intensity
Explanation: These cells react to the average light over time, which helps the SCN determine day length rather than responding to quick flashes.

Question 13

Mutations in which gene are linked to a shorter-than-normal circadian cycle and early sleep onset in humans?

A) TIM
B) CLOCK
C) PER
D) CRY

Answer 13

Answer: C) PER
Explanation: Mutations in the PER gene cause a circadian cycle shorter than 24 hours, leading to early sleep and wake times.

Question 14

What is the biochemical effect of light on the circadian rhythm at the molecular level in Drosophila?

A) Light increases the production of PER protein
B) Light activates a chemical that breaks down TIM protein
C) Light inhibits the production of PER and TIM mRNA
D) Light directly synthesizes melatonin in the SCN

Answer 14

Answer: B) Light activates a chemical that breaks down TIM protein
Explanation: Light triggers the breakdown of TIM, reducing sleep-promoting signals and adjusting the clock to match external light cues.

Question 15

Which gland releases melatonin under the control of the SCN, and how does melatonin affect diurnal animals like humans?

A) Hypothalamus; increases alertness
B) Thalamus; increases wakefulness
C) Pineal gland; increases sleepiness
D) Pituitary gland; suppresses melatonin production

Answer 15

Answer: C) Pineal gland; increases sleepiness
Explanation: The SCN signals the pineal gland to release melatonin at night, promoting sleepiness in diurnal species like humans.

Question 16

Why does exposure to blue light (such as from screens) late in the evening often delay sleep onset?

A) Blue light increases melatonin secretion
B) Blue light suppresses activity of melanopsin-containing ganglion cells
C) Blue light stimulates melanopsin-containing ganglion cells, phase-delaying the circadian rhythm
D) Blue light accelerates TIM protein production

Answer 16

Answer: C) Blue light stimulates melanopsin-containing ganglion cells, phase-delaying the circadian rhythm
Explanation: Blue light overstimulates these cells, signaling the SCN that it’s still daytime, thus delaying sleep.

Question 17

What brain structure is primarily responsible for generating the circadian rhythm?
A) Pineal gland
B) SCN (Suprachiasmatic Nucleus)
C) Thalamus
D) Hippocampus

Answer 17

Answer: B
Explanation: The SCN of the hypothalamus serves as the brain’s internal clock, coordinating circadian rhythms based on light cues.

Question 18

Why does REM sleep appear paradoxical?
A) It has both high and low levels of muscle tone
B) The brain is inactive while the body is hyperactive
C) The brain is highly active, but the body is deeply relaxed
D) Both heart rate and brain activity decrease dramatically

Answer 18

Answer: C
Explanation: In REM sleep, brain activity resembles wakefulness, yet the muscles are profoundly relaxed — a paradoxical combination.

Question 19

Which EEG pattern is most characteristic of relaxed wakefulness?
A) Beta waves
B) Alpha waves
C) Theta waves
D) Delta waves

Answer 19

Answer: B
Explanation: Alpha waves (8–12 Hz) dominate during a relaxed, calm but awake state.

Question 20

During which sleep stage are K-complexes and sleep spindles most prominent?
A) Stage 1
B) Stage 2
C) Slow-wave sleep (Stage 3/4)
D) REM sleep

Answer 20

Answer: B
Explanation: Stage 2 sleep is defined by the presence of K-complexes (sharp waves) and sleep spindles (brief bursts of rapid activity), important for memory consolidation.

Question 21

What is the primary function of sleep spindles according to research?
A) Initiate REM sleep
B) Regulate breathing patterns during sleep
C) Consolidate certain types of memory
D) Synchronize cardiac rhythms during sleep

Answer 21

Answer: C
Explanation: Sleep spindles are linked to memory consolidation and improvements in learning after sleep.

Question 22

What best distinguishes a minimally conscious state from a vegetative state?
A) Absence of any autonomic responses
B) Presence of brief periods of purposeful behavior
C) Complete loss of breathing
D) Regular periods of REM sleep

Answer 22

Answer: B
Explanation: In a minimally conscious state, patients show some awareness and brief purposeful actions, unlike vegetative patients.

Question 23

In which sleep stage is neuronal activity most synchronized?
A) REM sleep
B) Stage 1
C) Stage 2
D) Slow-wave sleep (Stages 3 and 4)

Answer 23

Answer: D
Explanation: Slow-wave sleep is marked by highly synchronized, large-amplitude brain waves, indicating coordinated neuronal activity.

Question 24

How does the pattern of REM sleep change across a full night’s sleep?
A) REM dominates early, then decreases
B) REM stays consistent in each sleep cycle
C) REM periods lengthen as sleep progresses
D) REM disappears after the first few hours

Answer 24

Answer: C
Explanation: Later in the night, REM periods lengthen, especially toward morning.

Question 25

Which structure produces melatonin, and when is its secretion highest? A) SCN, during daylight B) Pineal gland, during darkness C) Pituitary gland, during REM sleep D) Hypothalamus, during slow-wave sleep

Answer 25

Answer: B Explanation: The pineal gland produces melatonin mostly at night, triggered by darkness and influenced by the SCN.

Question 26

Which brain structure’s damage would most directly impair cortical arousal by disrupting ascending axons to the forebrain? A) Medulla B) Basal forebrain C) Reticular formation D) Locus coeruleus

Answer 26

Answer: C) Reticular formation Explanation: The reticular formation has ascending axons that promote cortical arousal; its damage drastically decreases wakefulness.

Question 27

Which neurotransmitter released by the basal forebrain is primarily involved in stimulating wakefulness? A) Dopamine B) GABA C) Acetylcholine D) Histamine

Answer 27

Answer: C) Acetylcholine Explanation: Acetylcholine from the basal forebrain enhances wakefulness by exciting the thalamus and cortex.

Question 28

Orexin’s main role in sleep-wake regulation is to: A) Initiate waking from sleep B) Maintain wakefulness over time C) Promote rapid eye movement (REM) sleep D) Inhibit histamine release

Answer 28

Answer: B) Maintain wakefulness over time Explanation: Orexin is essential for sustaining prolonged periods of wakefulness but not for waking up initially.

Question 29

Which of the following best describes the action of the locus coeruleus during emotional arousal? A) It inhibits less active neurons while suppressing the active ones. B) It releases dopamine widely across the cortex. C) It releases norepinephrine to enhance attention to meaningful stimuli. D) It primarily promotes slow-wave sleep through GABA.

Answer 29

Answer: C) It releases norepinephrine to enhance attention to meaningful stimuli. Explanation: The locus coeruleus selectively boosts attention and memory through widespread norepinephrine release.

Question 30

During sleep, decreased sensory input to the cortex is mainly due to: A) Increased dopamine levels B) Hyperpolarization of thalamic neurons C) Enhanced acetylcholine release D) Reduced GABAergic activity

Answer 30

Answer: B) Hyperpolarization of thalamic neurons Explanation: Thalamic neurons become hyperpolarized during sleep, limiting the transmission of sensory signals to the cortex.

Question 31

What explains why waking up is generally faster than falling asleep? A) Faster norepinephrine turnover B) Circadian rhythm phase shift C) Stabilized ion concentrations promoting arousal D) Delayed release of GABA

Answer 31

Answer: C) Stabilized ion concentrations promoting arousal Explanation: Waking is quicker because once ion levels supporting wakefulness are reached, they remain stable.

Question 32

Sleepwalking most likely occurs because: A) The entire brain is uniformly awake B) GABAergic inhibition is strongest in the motor cortex C) Some areas like the motor cortex remain awake while others are asleep D) The frontal cortex is hyperactivated during slow-wave sleep

Answer 32

Answer: C) Some areas like the motor cortex remain awake while others are asleep Explanation: In sleepwalking, parts of the motor system are awake enough for movement, while the rest of the brain remains asleep.

Question 33

Which drug mechanism would most effectively promote sleep in humans? A) Activating orexin receptors B) Blocking norepinephrine release from the locus coeruleus C) Blocking orexin receptors D) Enhancing histamine signaling in the cortex

Answer 33

Answer: C) Blocking orexin receptors Explanation: Drugs like suvorexant help induce sleep by inhibiting orexin signaling, which sustains wakefulness.

Question 34

In the phenomenon of sleep paralysis, why does temporary paralysis occur upon waking? A) Persistent hyperpolarization of thalamic neurons B) Continued inhibition of spinal motor neurons by the pons C) Overactivation of the locus coeruleus D) Excessive GABAergic transmission across the cortex

Answer 34

Answer: B) Continued inhibition of spinal motor neurons by the pons Explanation: Sleep paralysis happens when REM-related inhibition of muscles persists even after most of the brain awakens.

Question 35

Which brain structure’s damage would most directly impair cortical arousal by disrupting ascending axons to the forebrain? A) Medulla B) Basal forebrain C) Reticular formation D) Locus coeruleus

Answer 35

Answer: C) Reticular formation Explanation: The reticular formation has ascending axons that promote cortical arousal; its damage drastically decreases wakefulness.

Question 36

Which neurotransmitter released by the basal forebrain is primarily involved in stimulating wakefulness? A) Dopamine B) GABA C) Acetylcholine D) Histamine

Answer 36

Answer: C) Acetylcholine Explanation: Acetylcholine from the basal forebrain enhances wakefulness by exciting the thalamus and cortex.

Question 37

Which of the following best describes the action of the locus coeruleus during emotional arousal? A) It inhibits less active neurons while suppressing the active ones. B) It releases dopamine widely across the cortex. C) It releases norepinephrine to enhance attention to meaningful stimuli. D) It primarily promotes slow-wave sleep through GABA

Answer 37

Answer: C) It releases norepinephrine to enhance attention to meaningful stimuli. Explanation: The locus coeruleus selectively boosts attention and memory through widespread norepinephrine release.

Question 38

During sleep, decreased sensory input to the cortex is mainly due to: A) Increased dopamine levels B) Hyperpolarization of thalamic neurons C) Enhanced acetylcholine release D) Reduced GABAergic activity

Answer 38

Answer: B) Hyperpolarization of thalamic neurons Explanation: Thalamic neurons become hyperpolarized during sleep, limiting the transmission of sensory signals to the cortex.

Question 39

What explains why waking up is generally faster than falling asleep? A) Faster norepinephrine turnover B) Circadian rhythm phase shift C) Stabilized ion concentrations promoting arousal D) Delayed release of GABA

Answer 39

Answer: C) Stabilized ion concentrations promoting arousal Explanation: Waking is quicker because once ion levels supporting wakefulness are reached, they remain stable.

Question 40

Sleepwalking most likely occurs because: A) The entire brain is uniformly awake B) GABAergic inhibition is strongest in the motor cortex C) Some areas like the motor cortex remain awake while others are asleep D) The frontal cortex is hyperactivated during slow-wave sleep

Answer 40

Answer: C) Some areas like the motor cortex remain awake while others are asleep Explanation: In sleepwalking, parts of the motor system are awake enough for movement, while the rest of the brain remains asleep.

Question 41

Which drug mechanism would most effectively promote sleep in humans? A) Activating orexin receptors B) Blocking norepinephrine release from the locus coeruleus C) Blocking orexin receptors D) Enhancing histamine signaling in the cortex

Answer 41

Answer: C) Blocking orexin receptors Explanation: Drugs like suvorexant help induce sleep by inhibiting orexin signaling, which sustains wakefulness.

Question 42

In the phenomenon of sleep paralysis, why does temporary paralysis occur upon waking? A) Persistent hyperpolarization of thalamic neurons B) Continued inhibition of spinal motor neurons by the pons C) Overactivation of the locus coeruleus D) Excessive GABAergic transmission across the cortex

Answer 42

Answer: B) Continued inhibition of spinal motor neurons by the pons Explanation: Sleep paralysis happens when REM-related inhibition of muscles persists even after most of the brain awakens.

Question 43

During lucid dreaming, increased activity particularly in the ______ enables conscious monitoring of dreams. A) Reticular formation B) Temporal and frontal cortex C) Hypothalamus D) Basal forebrain

Answer 43

Answer: B) Temporal and frontal cortex Explanation: Increased 40 Hz activity in frontal and temporal regions allows awareness and some control during lucid dreaming.

Question 44

A patient violently thrashes during REM sleep, acting out dreams of defending themselves. Which neurotransmitter imbalance is most likely implicated? A) Excess dopamine B) Decreased GABAergic inhibition C) Increased serotonin activity D) Decreased acetylcholine release

Answer 44

Answer: B Explanation: REM Behavior Disorder is linked to deficient GABA and inhibitory transmission, leading to loss of muscle atonia during REM sleep.

Question 45

Night terrors most often occur during which stage of sleep? A) REM sleep B) Stage 1 NREM C) Stage 2 NREM D) Slow-wave (deep) NREM sleep

Answer 45

Answer: D Explanation: Night terrors typically happen during slow-wave sleep (deep NREM), not during dreaming REM sleep.

Question 46

Which sleep disorder is most associated with partial brain arousal, allowing complex but poorly planned actions without memory of the event? A) REM Behavior Disorder B) Night Terror C) Sleepwalking D) Periodic Limb Movement Disorder

Answer 46

Answer: C Explanation: Sleepwalking involves parts of the brain being awake while others are asleep, leading to uncoordinated but complex behaviors without later memory.

Question 47

Which statement about sleep sex ("sexsomnia") is most accurate based on current understanding? A) It is always associated with REM sleep. B) It is primarily caused by excessive REM atonia. C) It may result from sudden partial arousal during NREM sleep. D) It only occurs in people who have no history of sleepwalking.

Answer 47

Answer: C Explanation: Sexsomnia often happens after a partial arousal during NREM sleep, sometimes related to sleep apnea or drug side effects.

Question 48

In which disorder would you most likely see injuries to oneself or others due to dream enactment behavior? A) Night Terrors B) REM Behavior Disorder C) Periodic Limb Movement Disorder D) Sleepwalking

Answer 48

Answer: B Explanation: REM Behavior Disorder involves acting out dreams, which can cause injuries because muscles are not properly paralyzed during REM sleep.

Question 49

Which condition is characterized by movements every 20–30 seconds over minutes or hours, mainly during NREM sleep? A) Sleepwalking B) Periodic Limb Movement Disorder C) REM Behavior Disorder D) Sexsomnia

Answer 49

Answer: B Explanation: Periodic Limb Movement Disorder involves repetitive limb jerks at regular intervals, especially during NREM sleep.

Question 50

Which of the following is NOT a primary function of sleep based on current research? A) Strengthening memories B) Performing cellular maintenance in neurons C) Increasing metabolic activity D) Reorganizing synapses

Answer 50

Answer: C) Increasing metabolic activity Explanation: Sleep actually decreases metabolism to conserve energy.

Question 51

Sleep deprivation can mimic which of the following conditions, according to research? A) Alcohol intoxication B) Food poisoning C) Stroke D) Severe dehydration

Answer 51

Answer: A) Alcohol intoxication Explanation: Sleep-deprived driving is comparable to driving under the influence of alcohol.

Question 52

According to the evolutionary perspective, what is considered the original primary function of sleep? A) Memory consolidation B) Cellular repair C) Energy conservation D) Immune system activation

Answer 52

Answer: C) Energy conservation Explanation: Sleep likely evolved primarily to conserve energy during inefficient or dangerous times for activity.

Question 53

What is the main function of sleep in relation to memory? A) Sleep prevents memory from being formed B) Sleep consolidates and strengthens memory C) Sleep is irrelevant to memory consolidation D) Sleep causes complete memory loss

Answer 53

Answer: B) Sleep consolidates and strengthens memory Explanation: Sleep plays a crucial role in improving memory by solidifying and enhancing learned information.

Question 54

According to research, what happens when individuals learn something and then sleep afterward? A) They forget all the information B) Their memory becomes worse than before C) Their memory consolidates and improves D) Their brain activity is completely inactive during sleep

Answer 54

Answer: C) Their memory consolidates and improves Explanation: Studies show that sleeping after learning helps solidify memories and even improves recall.

Question 55

How does REM sleep contribute to memory? A) REM sleep has no impact on memory B) REM sleep weakens memory connections C) REM sleep helps consolidate and strengthen memories D) REM sleep only helps with physical recovery, not memory

Answer 55

Answer: C) REM sleep helps consolidate and strengthen memories Explanation: REM sleep plays a role in consolidating and strengthening memories, although it is not the only sleep stage responsible for memory enhancement.

Question 56

What is the primary hypothesis behind dreams in the Activation-Synthesis Theory? A) Dreams are a result of spontaneous brain activity interpreted by the cortex B) Dreams occur due to external stimuli during sleep C) Dreams represent a direct reflection of waking life experiences D) Dreams occur solely due to emotional disturbances

Answer 56

Answer: A) Dreams are a result of spontaneous brain activity interpreted by the cortex Explanation: The Activation-Synthesis Theory suggests that dreams occur because the brain tries to make sense of random neural activity during sleep.

Question 57

According to the Neurocognitive Hypothesis, what causes dreams? A) Dreams occur from external sensory input during sleep B) Dreams are random and unrelated to previous memories C) Dreams are a form of thinking influenced by recent memories D) Dreams are a form of hallucination with no connection to reality

Answer 57

Answer: C) Dreams are a form of thinking influenced by recent memories Explanation: The Neurocognitive Hypothesis suggests that dreams are a form of thought generated from recent experiences and memories.

Question 58

Which of the following best describes the role of REM sleep in relation to eye health? A) REM sleep prevents all eye problems B) REM sleep shakes the eyes to provide oxygen to the corneas C) REM sleep contributes to vision enhancement D) REM sleep has no connection to eye health

Answer 58

Answer: B) REM sleep shakes the eyes to provide oxygen to the corneas Explanation: According to one hypothesis, REM sleep helps maintain eye health by moving the eyes and providing oxygen to the corneas.