Deck 10: Fat-Soluble Vitamins

Question 1

How will retinol, once secreted from the liver, be found in the blood?

A) attached to RBP and transthyretin
B) attached to albumin
C) attached to a chylomicron
D) attached to RBP and stellate cells

Answer 1

A

Question 2

Within the nucleus, all trans-retinoic acid and/or 9-cis retinoic acid binds to _____.

A) nuclear retinoic acid receptors
B) mannosylated glycoproteins
C) cell aggregates
D) transcription factors

Answer 2

A

Question 3

The majority of vitamin A is stored in the liver, while carotenoids are stored mainly in the _____ tissue.

A) muscle
B) eye
C) adipose
D) skin

Answer 3

C

Question 4

Which is retinyl palmitate?

A) A
B) B
C) C
D) D
E) E

Question 5

Which is NOT related to the functions of vitamin A?

A) neurological function
B) growth
C) immunity
D) cell differentiation

Question 6

What happens to retinal in the enterocyte?

A) it is esterified
B) it is reduced to retinol
C) it is transported into the portal blood
D) 15, 15' dioxygenase acts to form beta-carotene

Question 7

Which vitamin is said to be essential for growth and immune system function?

A) K
B) A
C) D
D) E

Question 8

In what cells will you find most of the retinol and vitamin A stored?

A) stellate
B) gallbladder
C) fundus
D) antrum

Question 9

Which of the following is needed for the visual cycle?

A) 11-cis retinal
B) 9-cis retinoic acid
C) lycopene
D) cryptoxanthin

Question 10

Which vitamin directs cellular differentiation of epithelial cells?

A) riboflavin
B) vitamin K
C) vitamin E
D) vitamin A

Question 11

Which is retinoic acid?

A) A
B) B
C) C
D) D
E) E

Question 12

Why is retinoic acid considered a hormone?

A) It has receptors on the nucleus and causes a change in protein synthesis.
B) It has a biologic function similar to insulin.
C) It is synthesized in the same tissue that it affects.
D) It causes the catabolism (break down) of body proteins.

Question 13

Choose the food that is high in vitamin A palmitate.

A) spinach
B) liver
C) carrots
D) pumpkin

Question 14

Which is β-carotene?

A) A
B) B
C) C
D) D
E) E

Question 15

Which of the carotenoid pigments has the greatest vitamin A activity?

A) alpha-carotene
B) beta-carotene
C) gamma-carotene
D) delta-carotene

Question 16

Choose the ONE correct statement.

A) Beta-carotene is hydrolyzed in the jejunum before it is absorbed.
B) Retinol does not need to form a micelle to cross the USW.
C) Beta-carotene dioxygenase activity occurs in the lumen of the ileum.
D) Retinol must be re-esterified to be carried in the chylomicron.

Question 17

Where would you find retinoid X receptors (RXR)?

A) cytosol
B) nucleus
C) mitochondria
D) none of the above

Question 18

In order to be carried in the chylomicron, retinol (once in the enterocyte) is _____.

A) esterified by lecithin retinol acyl transferase
B) converted to retinaldehyde by retinaldehyde reductase
C) attached to a VLDL
D) attached to an RXR receptor on the nucleus

Question 19

Choose the correct statement about the quenching of singlet oxygen by carotenoids.

A) Carotenoids donate an electron to the singlet oxygen to make it stable.
B) Carotenoids covalently bond with the singlet oxygen to make it stable.
C) Carotenoids donate energy so that the excited electron returns to its orbital.
D) Carotenoids absorb the extra energy that is held by the singlet oxygen.

Question 20

Formation of retinol from beta-carotene requires the presence of what B vitamin?

A) ascorbic acid
B) folic acid
C) niacin
D) pyridoxal phosphate

Question 21

Which symptom of a vitamin A deficiency is most likely responsible for deficiency-related deaths?

A) its function as a teratogen
B) poor cellular differentiation and growth
C) keratinization of the cornea
D) severe infections

Question 22

Which is the strongest antioxidant?

A) beta-carotene
B) alpha-tocopherol
C) beta-cryptoxanthin
D) lycopene

Question 23

The vitamin D response element (VDRE) is found

A) on the enterocyte membrane.
B) on the renal tubule.
C) in the nucleus.
D) in the pancreatic duct cell.

Question 24

What % of vitamin D from the diet is absorbed?

A) 20
B) 30
C) 40
D) 50

Question 25

Choose the phrase which best explains the following statement: "β-carotene is no magic bullet."

A) β-carotene does not decrease the reactivity of singlet oxygen molecules.
B) β-carotene is not the only health-promoting molecule in fruits and vegetables.
C) β-carotene supplements cannot be manufactured cheaply enough.
D) β-carotene can replace vitamin E in terminating the auto-oxidation of fatty acids.

Question 26

Which vitamin is believed to function like a steroid hormone?

A) choline
B) vitamin A
C) vitamin D
D) vitamin E

Question 27

Choose the non-genomic effect of vitamin D.

A) increased synthesis of calbindin
B) bone accretion
C) rapid calcium absorption
D) intracellular cytosolic signal transduction

Question 28

Which micromineral deficiency interferes with vitamin A metabolism by reducing retinol-binding protein?

A) manganese
B) zinc
C) selenium
D) iron

Question 29

Dietary cholecalciferol must be further hydroxylated in order to be active vitamin D. The first hydroxylation occurs in the _____ to produce _____.

A) liver, 25-hydroxycholecalciferol
B) kidney, 25-hydroxycholecalciferol
C) skin, 7-dehydrocholesterol
D) kidney, 1-hydrocholesterol

Question 30

Would you recommend β-carotene supplementation to a smoker to decrease risk to lung cancer?

A) Yes-β-carotene can quench singlet oxygen.
B) Yes-smoking increases free radical formation; β-carotene can decrease free radicals.
C) No-β-carotene supplements may be harmful to smokers and are their use is not advised for the general public.
D) No-β-carotene supplements can cause a vitamin A toxicity and liver cirrhosis.

Question 31

Which vitamin D molecule would you expect to see in fortified foods?

A) ergocalciferol - vitamin D₂
B) calcidiol - 25-OH D₃
C) calcitriol - 1,25-OH₂ D₃
D) cholecalciferol - vitamin D₃

Question 32

An individual with poor vitamin A status would have a _____ RDR than someone with a good vitamin A status.

A) greater
B) lesser

Question 33

Which is the best technique to assess status of vitamin A liver stores?

A) serum retinol levels
B) the relative dose response
C) clinical eye examinations

Question 34

Imagine you are a nutritionist working in a country other than the U.S. Which is an assumption about vitamin D status that is NOT true?

A) The latitude makes a difference as regards how much vitamin D can be self-synthesized.
B) Customs of dress make a difference as regards how much vitamin D can be self-synthesized.
C) Cow's milk is a reliable source of vitamin D in the food supply.
D) Skin color makes a difference as regards how much sun is needed to synthesize vitamin D.

Question 35

It's a good thing that milk is fortified with vitamin D so that we can consume the RDA if we drink the recommended number of glasses of milk each day. The DRI for 9-69 year olds is 600 IU (15 $\mu$ g). This equals _____ cups of milk.

A) two
B) three
C) four
D) six

Question 36

What form of vitamin D is the major circulating form with a half-life of approximately 3 weeks?

A) calcidiol
B) calcitriol
C) cholecalciferol
D) vitamin D₂

Question 37

Which vitamin has as its primary function the maintenance of calcium homeostasis?

A) A
B) D
C) E
D) K