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Q:
Free radicals take electrons from all of the following EXCEPT _____.
a. calcitriol
b. DNA
c. proteins
d. PUFAs
Q:
Why are vitamins A and E said to be antagonists of vitamin K?
Q:
Discuss the role of calcitonin in maintaining normal blood calcium concentration.
Q:
Explain the process by which rhodopsin is formed.
Q:
Although for micronutrients increasing the amount of a protein by directly inducing gene expression is certainly a common mechanism, we have encountered other mechanisms by which vitamins can regulate proteins. Provide one example of posttranslational modification, being as specific as possible.
Q:
Regulation of Proteins by Vitamins. Micronutrients, like vitamins, typically regulate gene expression (i.e., induction) directly. Use either vitamin D or vitamin A to illustrate this conceptbe complete and thorough in your answer. Don"t just draw a diagram without some discussion and make sure everything is labeled and/or defined.
Q:
Indicate: (1) the active form of vitamin K, (2) the general function of vitamin K, and (3)an example of the general function (this could be a specific reaction or simply indicate a pathway/ process where it occurs). Your answers do not need to be long!
Q:
The absorbed carotenoids that enter the liver can follow three routes: _____, _____ and _____.
Q:
The active form of vitamin A that regulates cell differentiation through gene expression is _____.
Q:
The 2 forms of naturally occurring provitamin D are: _____ and _____.
Q:
When serum Ca is low, the synthesis of the hormone _____ is stimulated in the kidney to restore serum Ca to normal.
Q:
The synthesis of the specific bone protein osteocalcin is dependent on the presence of three fat-soluble vitamins: _____, _____, and _____.
Q:
Match each vitamer with its function.Vitamer1) 11-cis retinal2) retinoic acid3) alpha-tocopherol4) calcitriol5) hydroquinone (KH2)Functiona. interacts with nuclear VDR to increase calbindin b. required for carboxylation of glutamic acid c. needed for binding with opsin in the photoreceptor rod cells d. transported into nucleus to affect gene transcription of keratin proteins e. donates hydrogens to terminate propagation of membrane lipid peroxidation chain reactions
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
7-dehydrocholesterol is the form of vitamin D that is added to fortify milk.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
A good source of vitamin D is milk, because it is fortified with 1,25-(OH)2-vitamin D3.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
All of the functions of vitamin A are carried out by retinoic acid via transcriptional mechanisms.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Many anticoagulants work by inhibiting the regeneration of active vitamin K (i.e., dihydrovitamin KH2) during the vitamin K cycle.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Rhodopsin is simply the opsin protein after it has been activated by 11-cis-retinal.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Vitamin D increases the abundance of calbindin (Ca++ transporter) in enterocytes by increasing the transcription of the calbindin gene.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
All three forms of vitamin A (retinol, retinal, retinoic acid) are stored in the liver as retinyl esters.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Many anticoagulants inhibit the vitamin K cycle, thereby preventing activation of clotting proteins.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Calcium homeostasis in the blood depends on intestinal absorption, bone resorption, and kidney reabsorption.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Production of active vitamin D requires skin, sunlight, cholesterol, the liver, and the kidneys.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.Because -carotene can be converted into retinol, plant sources are referred to as preformed vitamin A.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Gut bacteria can produce some vitamins, but this rarely contributes to our requirements because they are not absorbed.
Q:
Induction of a protein (i.e., increasing the amount of a protein) via increasing gene expression can be accomplished by:
a. vitamin A.
b. folate.
c. vitamin C.
d. more than one of these vitamins
Q:
Which is the best measure of vitamin K status?a. des--carboxyglutamic prothrombinb. prothrombin timec. INRd. PTH concentration
Q:
For which vitamin is a severe deficiency associated with an increased tendency for bleeding?
a. A
b. D
c. E
d. K
Q:
Vitamin K deficiency in adults is most likely due to:
a. oxalic acid in food.
b. achlorhydria.
c. antibiotic therapy.
d. a high-fiber diet.
Q:
Risk of vitamin K deficiency is greatest in:
a. newborns.
b. children.
c. adolescents.
d. older people.
Q:
Mr. S. takes warfarin due to his valve replacement surgery. He is an avid gardener and enjoys eating the many green leafy vegetables he grows. You caution Mr. S. to tell his physician about this because the amount of warfarin he takes may need to be _____
a. decreased
b. increased
Q:
Anticoagulant drugs that act by inhibiting vitamin K activity do so by which mechanism?
a. inhibiting the formation of the active form of vitamin K
b. interfering with micelle formation so vitamin K is not absorbed
c. not allowing calcium to interact with Gla residues
d. stimulating osteocalcin synthesis
Q:
The action of vitamin K is the post-translational synthesis of blood clotting factors occurs:
a. in the blood.
b. in the liver.
c. in the small intestine.
d. in the bone marrow.
Q:
Which fat-soluble vitamin appears to operate as a coenzyme that modifies proteins to bind with calcium?a. Ab. -carotenec. Ed. K
Q:
Which of the fat-soluble vitamins is consumed in the form of phylloquinone from plant foods?
a. A
b. D
c. E
d. K
Q:
For which vitamin is the Tolerable Upper Intake Level set because of increased tendency for bleeding?
a. A
b. D
c. E
d. K
Q:
Which vitamin is associated with improved plasma membrane structure and glucose transport/metabolic control in people with type 2 diabetes?
a. A
b. D
c. E
d. K
Q:
Which fat-soluble vitamin has as its principal function the maintenance of membrane integrity?
a. vitamin D
b. vitamin E
c. vitamin A
d. vitamin K
Q:
In what type of tissue is the largest amount of vitamin E stored?
a. adipose
b. heart
c. lung
d. brain
Q:
Immediately following a balanced meal that contained vitamin E (such as fortified milk), where would you most likely find most of the vitamin E in the body?
a. in the portal blood as α-tocopherol
b. in the general circulation bound to RBC
c. inside cells as free α-tocopherol
d. stored in adipose tissue
e. in chylomicrons in the lymphatic vessels and general circulation
Q:
A genetic deficiency in _____ leads to a vitamin E deficiency syndrome.
a. RRR alpha-tocopherol
b. gamma-tocotrienol
c. tocopherol carrier protein in the jejunum
d. alpha-tocopherol transfer protein in the liver
Q:
Who discovered vitamin E?
a. Evans and Bishop
b. McCollum and Davis
c. Mellanby and Hopkins
d. Simon and Garfunkel
Q:
How does alpha-tocopherol differ from beta-tocopherol?
a. saturation of side chain
b. location of methyl groups
c. source in the diet
Q:
Which tocopherol form provides the most vitamin E activity in the U.S. food supply?
a. alpha
b. beta
c. gamma
d. delta
Q:
In assessing the vitamin D status of an individual, which measure would you use?
a. circulating 25-OH cholecalciferol
b. circulating 1,25-OH2 cholecalciferol
c. circulating cholecalciferol
d. serum calcium levels
Q:
Sun exposure does not cause hypervitaminosis D because _____.
a. cutaneous production of the vitamin reaches a maximum
b. sunburned skin is not sensitive to the UV wavelength that causes previtamin D3 synthesis
c. inactive products are synthesized from pre-vitamin D3 and D3
d. vitamin D-binding protein is not saturated with D3
Q:
What is a symptom of a vitamin D toxicity?
a. hypercalcemia
b. hypocalcemia
c. rickets
d. osteoporosis
Q:
Toxicity of which vitamin is related to increased deposition of calcium in soft tissues?
a. lipoic acid
b. biotin
c. D
d. E
Q:
A deficiency of which vitamin is commonly associated with rickets?
a. A
b. D
c. E
d. K
Q:
If asked about the relationship of vitamin D to autoimmune disease, the best information for a dietetic professional to provide is:
a. the evidence does not support a relationship at this time.
b. the evidence is only in animals, not humans.
c. some evidence suggests a protective effect of vitamin D.
d. take a supplement containing 2000 IU vitamin D each day.
Q:
The RDA for vitamin D for people over the age of 70 is _____ the RDA for teenagers.
a. greater than
b. less than
c. equal to
Q:
What vitamin is associated with diminished proliferation and enhanced differentiation of cells, which serves as a basis for its use as treatment of skin diseases such as psoriasis?
a. A
b. E
c. K
d. D
Q:
Choose the correct order of the phrases below to explain the response of the body to a decline in serum calcium levels. Choose the BEST answer.
1) Increased release of PTH
2) Decreased release of PTH
3) Increased synthesis of calbindin
4) Increased synthesis of 1,25-(OH)2 D3
5) Increased bone absorption
6) Increased calcium absorption
7) Decreased bone resorption
8) Increased calcium excretion
9) Increased bone resorption
a. 1, 5, 4, 8
b. 1, 3, 5, 9
c. 2, 3, 9, 6
d. 1, 4, 3, 6
Q:
Which vitamin has as its primary function the maintenance of calcium homeostasis?
a. A
b. D
c. E
d. K
Q:
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.
Q:
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
Q:
Which vitamin is believed to function like a steroid hormone?
a. choline
b. vitamin A
c. vitamin D
d. vitamin E
Q:
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
Q:
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
Q:
What % of vitamin D from the diet is absorbed?
a. 20
b. 30
c. 40
d. 50
Q:
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 g). This equals _____ cups of milk.a. twob. threec. fourd. six
Q:
Which vitamin D molecule would you expect to see in fortified foods?a. ergocalciferol - vitamin D2b. calcidiol - 25-OH D3c. calcitriol - 1,25-OH2 D3d. cholecalciferol " vitamin D3
Q:
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.
Q:
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
Q:
An individual with poor vitamin A status would have a _____ RDR than someone with a good vitamin A status.
a. greater
b. lesser
Q:
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
Q:
Which micromineral deficiency interferes with vitamin A metabolism by reducing retinol-binding protein?
a. manganese
b. zinc
c. selenium
d. iron
Q:
Choose the phrase which best explains the following statement: "-carotene is no magic bullet."a. -carotene does not decrease the reactivity of singlet oxygen molecules.b. -carotene is not the only health-promoting molecule in fruits and vegetables.c. -carotene supplements cannot be manufactured cheaply enough.d. -carotene can replace vitamin E in terminating the auto-oxidation of fatty acids.
Q:
Would you recommend β-carotene supplementation to a smoker to decrease risk to lung cancer?
a. Yesβ-carotene can quench singlet oxygen.
b. Yessmoking increases free radical formation; β-carotene can decrease free radicals.
c. Noβ-carotene supplements may be harmful to smokers and are their use is not advised for the general public.
d. Noβ-carotene supplements can cause a vitamin A toxicity and liver cirrhosis.
Q:
Which is the strongest antioxidant?
a. beta-carotene
b. alpha-tocopherol
c. beta-cryptoxanthin
d. lycopene
Q:
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.
Q:
Which is NOT related to the functions of vitamin A?
a. neurological function
b. growth
c. immunity
d. cell differentiation
Q:
Which vitamin is said to be essential for growth and immune system function?
a. K
b. A
c. D
d. E
Q:
Where would you find retinoid X receptors (RXR)?
a. cytosol
b. nucleus
c. mitochondria
d. none of the above
Q:
Which vitamin directs cellular differentiation of epithelial cells?
a. riboflavin
b. vitamin K
c. vitamin E
d. vitamin A
Q:
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.
Q:
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
Q:
Complete the following paragraph with the choices given.Vitamin A functions in the visual cycle. This mechanism involves a vitamin A molecule called A , combining with B to form C . When photon energy strikes this molecule, it splits and causes a conformational change in the molecule, causing an electrical signal to be sent to the brain.Blank Aa. rhodopsinb. 11-cis retinalc. all-trans retinald. retinole. opsinf. retinoic acidBlank Ba. rhodopsinb. 11-cis retinalc. all-trans retinald. retinole. opsinf. retinoic acidBlank Ca. rhodopsinb. 11-cis retinalc. all-trans retinald. retinole. opsinf. retinoic acid
Q:
Which of the following is needed for the visual cycle?
a. 11-cis retinal
b. 9-cis retinoic acid
c. lycopene
d. cryptoxanthin
Q:
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