FNDH 620 - Final Exam
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
,FNDH 620 - Final Exam
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%).
,FNDH 620 - Final Exam
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.
, FNDH 620 - Final Exam
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 pathway for it to become vitamin D? - Sun
- skin
-- 7-dehydrocholesterol
--- liver: 1st hydroxylation
---- kidney: 2nd hydroxylation
----- 1, 25(OH)2VitD3
------ Metabolically active form
What is the most potent vitamin D metabolite? - 1,25-dihydroxycholecalciferol
Functions of vitamin D - - regulation of gene expression
- affects calcium & phosphate homeostasis
- differentiation of stem cells in bone tissue
- differentiation of hair follicles & skin cells
AI recommendation for vitamin D in infants to 50yrs - 5 mcg/day
AI recommendation for vitamin D in > 50yrs - 15 mcg/day
AI recommendation for vitamin D in > 70yrs - 20 mcg/day
UL recommendation for vitamin D in > 9yr - 50-100 mcg
What diseases are caused by vitamin D deficiency? - - Rickets
- Osteomalacia
Failure of growing bones to mineralize properly. This results in bowing of long, weight-
bearing bones. - Rickets
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
,FNDH 620 - Final Exam
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%).
,FNDH 620 - Final Exam
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.
, FNDH 620 - Final Exam
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 pathway for it to become vitamin D? - Sun
- skin
-- 7-dehydrocholesterol
--- liver: 1st hydroxylation
---- kidney: 2nd hydroxylation
----- 1, 25(OH)2VitD3
------ Metabolically active form
What is the most potent vitamin D metabolite? - 1,25-dihydroxycholecalciferol
Functions of vitamin D - - regulation of gene expression
- affects calcium & phosphate homeostasis
- differentiation of stem cells in bone tissue
- differentiation of hair follicles & skin cells
AI recommendation for vitamin D in infants to 50yrs - 5 mcg/day
AI recommendation for vitamin D in > 50yrs - 15 mcg/day
AI recommendation for vitamin D in > 70yrs - 20 mcg/day
UL recommendation for vitamin D in > 9yr - 50-100 mcg
What diseases are caused by vitamin D deficiency? - - Rickets
- Osteomalacia
Failure of growing bones to mineralize properly. This results in bowing of long, weight-
bearing bones. - Rickets
