Bio 432 Final Exam Questions with 100% Correct Answers
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Course
Bio 432
Institution
Bio 432
Light at night (LAN) & eating: Correct Answer Increase in ghrelin
Decrease in leptin
Leads to more eating and possible obesity
Experiment with LAN, rats & sugar water: Correct Answer Chronic low light at night
Rats preferred normal water > sugar water
Need ____ to make melatonin Correct...
Bio 432 Final Exam Questions with 100%
Correct Answers
Light at night (LAN) & eating: Correct Answer Increase in ghrelin
Decrease in leptin
Leads to more eating and possible obesity
Experiment with LAN, rats & sugar water: Correct Answer Chronic low light at night
Rats preferred normal water > sugar water
Need ____ to make melatonin Correct Answer Serotonin
Need _____ light to make 5-HT Correct Answer Blue
Blue light = _____ nm Correct Answer 480
Need ____ to make vitamin D Correct Answer UVB
UVB = _____ nm Correct Answer 295
To have a good, healthy sleep, we need 2 things: Correct Answer 1. Exposure to sun
during the day (not artificial light)
2. No exposure to light at night (esp blue light)
Why is LAN bad? Correct Answer Low levels of melatonin released
The study of circadian rhythms is called _____ Correct Answer Chronobiology
Light acts on body via 2 pathways: Correct Answer 1. Optic tract
2. Retinohypothalamic tract
Optic tract: Correct Answer Visual perception
Retinohypothalamic tract: Correct Answer Circadian, endocrine & neurobehaviour
Sensitive to blue light
Both acute & long-term
Light causes a chemical change in _____, which then causes a signal to be sent to
ganglion cells Correct Answer Melanopsin
5 main effects of light dysregulation: Correct Answer 1. Cardiovascular
2. Obesity
3. Depression
4. Insomnia
,5. Cancer (breast, prostate, colon)
Melatonin is secreted by the _____ to initiate sleep Correct Answer Pineal gland
The _____ controls melatonin production Correct Answer Suprachiasmatic nucleus
Suprachiasmatic nucleus: Correct Answer Once exposed to the first light of day, raises
body temp and releases stimulating hormones (ex. cortisol)
Delays release of melatonin until darkness
Melatonin & estrogen relationship: Correct Answer Melatonin is a regulator of ER and
estrogen production
5-HT is a ____ and a _____ Correct Answer NT
Hormone
Most 5-HT is produced in the _____; rest in the ____ Correct Answer Gut
CNS
5-HT is derived from _____ Correct Answer Tryptophan
Highest levels of 5-HT are seen during the morning/afternoon/night Correct Answer
Afternoon
5-HT acts as a *local regulator* of ______ Correct Answer Mammary gland epithelium
Vitamin D: Correct Answer Maintains *calcium & phosphorus* blood levels
Imp effects on cell differentiation & development
Metabolite of cholesterol, which is present in the skin when exposed to UVB (then
processed in liver & kidneys)
10% eaten
Structurally related to steroids, so uses a *nuclear receptor*
Signals for *anti-proliferation* (imp for understanding cancer)
_____ is the active form of vitamin D Correct Answer Calcitriol
Receptors of vit D found in 6 places: Correct Answer 1. Bone
2. Kidneys
3. Gut
4. Immune cells
5. Testes
,6. Breasts
Low levels of ____ & _____ associated with breast cancer (BC) Correct Answer
Melatonin
Vit D
Exposure to light is also dependent on ____ & _____ Correct Answer Latitude
Season
Not only does a lack of 5-HT during the day lead to a lack of melatonin at night, but so
does a lack of _____ Correct Answer Vit D
LAN is correlated with _____ & _____ cancer Correct Answer Breast
Prostate
Changes in exposure to light affects biological rhythms. Alters metabolism of 6
hormones: Correct Answer 1. GnRH
2. Estrogen
3. Progesterone
4. Testosterone (DHEA)
5. Vit D
6. Melatonin
Changes in exposure to light affects biological rhythms. Alters micronutrients, including
_____ Correct Answer Iron
Changes in exposure to light affects biological rhythms. Alters NTs including ____ &
____ Correct Answer DA
5-HT
Melatonin synthesis: (3) Correct Answer 1. Tryptophan is made into 5-HT by
*tryptophan-5-hydroxylase*
2. 5-HT is made into N-acetylserotonin by *serotonin-N-acetyltransferase*
3. N-acetylserotonin is made into melatonin
Melatonin can also be called ______ Correct Answer N-acetyl-5-hydroxytryptamine
For melatonin synthesis, what is the rate limiting step? Correct Answer 5-HT being
made into N-acetylserotonin
Vit D is circadian: Correct Answer Short half-life
Peaks after 12 pm (same with 5-HT & body temp)
Secosteroid hormone
*Seco*steroid hormone: Correct Answer "Broken" ring structure
Produced in liver
, _____ drugs reduce BC risk Correct Answer SSRIs
_____ is low in those with seasonal affective disorder (SAD) Correct Answer 5-HT
Synergy between melatonin, 5-HT & vit D: Correct Answer Need UVB to get Vit D
Vit D activates transcription of gene for *tryptophan-5-hydroxylase*
So need Vit D to get 5-HT to get melatonin
Pathway of LAN → BC risk: (6) Correct Answer 1. Lack of UVB
2. Low vit D
3. Low 5-HT
4. Low melatonin at night (esp if LAN)
5. Higher estrogen levels
6. Increased BC risk
5-HT & its role in lactation: Correct Answer Regulates lactation and initiates the
transition into the earliest phases of *involution* (apoptosis at end of menstruation)
Induces another hormone to allow mammary gland to drive the *mobilization of calcium*
from skeleton
*BC cells are resistant to apoptosis*
Progesterone & its role in lactation: Correct Answer If pregnant, high levels for milk
production
Shift work increases/decreases progesterone levels Correct Answer Increases
Melatonin suppresses GnRH release: Correct Answer Involves PKC and *extracellular
signal-related kinase 1&2*
Used GT1-7 cell line model
5 approaches to experimentally studying LAN: Correct Answer 1. Shift work
2. Epidemiology in different areas of world
3. Direct evidence that light INH melatonin
4. Animal models
5. Melatonin signalling pathways
BC risk in night-shift workers: Correct Answer Urinary MEL metabolite low in both nights
(working & not working)
Nurses who reported less tolerance to long shifts (ex. depression, insomnia, etc) had
lower melatonin levels
Possibly a genetic predisposition
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