FNDH 620 - Final Exam 2022
(COMPLETE SOLUTIONS)
True or False
Vitamins:
- cannot be made in the body
- noncaloric
- required in small amounts (mg and mcg) - ✔✔TRUE
Vitamins:
- cannot be made in the body
- noncal
...
FNDH 620 - Final Exam 2022
(COMPLETE SOLUTIONS)
True or False
Vitamins:
- cannot be made in the body
- noncaloric
- required in small amounts (mg and mcg) - ✔✔TRUE
Vitamins:
- cannot be made in the body
- noncaloric
- required in small amounts (mg and mcg)
What 3 forms can vitamin A take? - ✔✔- retinol (alcohol)
- retinal (aldehyde)
- retinoic acid (acid form from retinal)
What form of vitamin A is normally found in blood and tissues? - ✔✔Retinyl Palmitate
What form of vitamin A is found in plants? - ✔✔Previtamin A - carotenoid structure that includes the
carotenes and xanthophylls
- found in plants
- needs to be converted to active vitamin A
What is the most potent form of vitamin A? - ✔✔Beta carotene
Where can retinyl esters be found? - ✔✔Animal Products *only*
Where can vitamin A be found? - ✔✔Fortified milk and milk products
Where can previtamin A carotenoids be found? - ✔✔Plant sources - orange and dark green vegetables
Vitamin A containing micelles form and traverse the enterocyte plasma membrane by what type of
diffusion? - ✔✔Passive Diffusion
What two things are needed in the digestion of vitamin A? - ✔✔Bile and Fat
Beta-carotene and other carotenoids can be converted to retinol by what means? - ✔✔Beta-carotene
and other carotenoids can be converted to retinol by cleavage of the central double bond
When beta-carotene is cleaved, how many molecules of retinal does it make? - ✔✔1 beta-carotene = 2
retinal
Retinyl, retinyl esters, and carotenoids are packaged into what and transported where? - ✔✔Retinyl,
retinyl esters, and carotenoids are packaged in *chylomicrons* and transported in the *lymphatic
system*.
Vitamin A and carotenoids are metabolized where and as what? - ✔✔Vitamin A and carotenoids are
metabolized in the liver as chylomicron remnants.
Retinoic acid is absorbed and transported to which organ bound to what protein? - ✔✔Retinoic acid is
absorbed and transported to the liver bound to albumin.
The liver stores 90% of which vitamin? - ✔✔vitamin A
What are the functions of vitamin A & Carotenoids? - ✔✔- Improves vision
- Cell differentiation & cell proliferative activity
- Fights cancer
- Development of embryo tissue
- Synthesis of glycoproteins
- Reproductive processes
- Antioxidant capacity
- Bone development and maintenance
- Provides immunity
How is vitamin A essential to our vision? - ✔✔- retinol is transformed into 11-cis retinal through a series
of reactions
- 11-cis retinal combines with the protein opsin forming rhodopsin
- Rhodopsin + light changes the conformation of the protein which begins a cascade of events leading to
the generation of an action potential
- This action potential sends neural impulses to the optic center of the brain translating it into images
What are the 2 nuclear receptors that work with vitamin A on a molecular level? - ✔✔RAR & RXR
Vitamin A is beneficial for all cancers but... - ✔✔lung cancer
Vitamin A is involved in sperm development and differentiation, without it, what happens? -
✔✔Without RARγ, males are sterile
If a female is low or deficient in vitamin A, what could happen? - ✔✔deficiency: inability of implantation
of the egg
low: may allow implantation but may end in a miscarriage; various birth defects
Vitamin A is excreted in _____ & _____. - ✔✔Vitamin A is excreted in the bile (70%) and urine (30%).
RDA of vitamin A for men - ✔✔900 mcg/day
RDA of vitamin A for women - ✔✔700 mcg/day
12 mcg beta-carotene = ??? mcg of retinol - ✔✔12 mcg beta-carotene = 1 mcg of retinol
Vitamin A deficiency is the leading cause of ___________ in children worldwide. - ✔✔Vitamin A
deficiency is the leading cause of *non-accidental blindness* in children worldwide.
Diseases caused by vitamin A deficiency - ✔✔- night blindness
- xerophthalmia
- bitot spots
Symptoms of vitamin A toxicity - ✔✔- decreased appetite
- dry, itchy, flaky skin
- headache
- hair loss
- bone/muscle pain
- ataxia
- nausea/vomiting
- dry mouth
- eye irritations
- conjunctivitis
- birth defects
- miscarriage
- learning difficulities
This unique vitamin is synthesized in the body with adequate sun exposure as well as it's ability to
function as a hormone. - ✔✔Vitamin D
What are the two forms of vitamin D? - ✔✔D2 - ergocalciferol
D3 - cholecalciferol
UV light converts __________ into cholecalciferol (D2). - ✔✔UV light converts *7-dehydrocholesterol*
into cholecalciferol (D2).
Aside from humans being able to produce their own amounts of vitamin D, it can also be found in: - ✔✔-
animal foods (eggs, liver, fatty fish, & butter)
- fortified milk and dairy products
- fortified margarine
Vitamin D enters mucosal enterocytes by __________ diffusion. - ✔✔Vitamin D enters mucosal
enterocytes by *passive* diffusion.
Vitamin D becomes part of __________ and then enters the __________ circulation. - ✔✔Vitamin D
becomes part of *chylomicrons* and then enters the *lymph* circulation.
40% of vitamin D is transported in chylomicrons. The remaining 60% is transported by what protein? -
✔✔D-binding Protein (DBP)
- this is also the same protein that picks up vitamin D created in the skin
The efficiency of binding to vitamin D is increased after two ____________. - ✔✔The efficiency of
binding to vitamin D is increased after two *hydroxylations*.
Both the _____ and the _____ add a hydroxyl group to the vitamin D structure. - ✔✔Both the *liver*
and the *kidneys* add a hydroxyl group to the vitamin D structure.
When vitamin D levels are low, what becomes more efficient? - ✔✔25-hydroxylase
When light hits the skin, what is the pat
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