Accounting
Anthropology
Archaeology
Art History
Banking
Biology & Life Science
Business
Business Communication
Business Development
Business Ethics
Business Law
Chemistry
Communication
Computer Science
Counseling
Criminal Law
Curriculum & Instruction
Design
Earth Science
Economic
Education
Engineering
Finance
History & Theory
Humanities
Human Resource
International Business
Investments & Securities
Journalism
Law
Management
Marketing
Medicine
Medicine & Health Science
Nursing
Philosophy
Physic
Psychology
Real Estate
Science
Social Science
Sociology
Special Education
Speech
Visual Arts
Human Resource
Q:
In what cells will you find most of the retinol and vitamin A stored?
a. stellate
b. gallbladder
c. fundus
d. antrum
Q:
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
Q:
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
Q:
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.
Q:
What happens to retinal in the enterocyte?a. it is esterifiedb. it is reduced to retinolc. it is transported into the portal bloodd. 15, 15- dioxygenase acts to form beta-carotene
Q:
Formation of retinol from beta-carotene requires the presence of what B vitamin?
a. ascorbic acid
b. folic acid
c. niacin
d. pyridoxal phosphate
Q:
Use the molecules below to answer. ABCDEWhich is -carotene?a. Ab. Bc. Cd. De. E
Q:
Use the molecules below to answer.ABCDEWhich is retinoic acid?a. Ab. Bc. Cd. De. E
Q:
Use the molecules below to answer.ABCDEWhich is retinyl palmitate?a. Ab. Bc. Cd. De. E
Q:
Choose the food that is high in vitamin A palmitate.
a. spinach
b. liver
c. carrots
d. pumpkin
Q:
Which of the carotenoid pigments has the greatest vitamin A activity?
a. alpha-carotene
b. beta-carotene
c. gamma-carotene
d. delta-carotene
Q:
Vitamin C's actual participation in biochemical reactions usually involves its antioxidant ability. Choose the description of this activity.
a. Donates an electron or electrons to oxidize a mineral cofactor
b. Accepts an electron or electrons to reduce a mineral cofactor
c. Donates an electron or electrons to reduce a mineral cofactor
d. Accepts an electron from the quinone form of vitamin E
Q:
A primary function of vitamin C is to act as an:
a. antiviral agent.
b. antioxidant.
c. antirachitic agent.
d. acyl transferase.
Q:
Without enough vitamin C, collagen would _____.
a. be too tightly coiled
b. be over-hydroxylated
c. be under-hydroxylated
d. too strong and less flexible
Q:
Ascorbic acid provides a reducing equivalent so that iron is in the _____ form in lysyl hydroxylase.
a. ferric
b. ferrous
Q:
Which of the following molecules synthesized with the help of vitamin C underscores the importance of vitamin C to fat metabolism?
a. carnitine
b. collagen
c. tyrosine
d. norepinephrine
Q:
Which water-soluble vitamin contributes to "intracellular cement" in the formation of scar tissue and wound healing?
a. thiamin
b. riboflavin
c. vitamin C
d. vitamin B12
Q:
Although excess absorbed ascorbic acid is excreted in urine, the body has an estimated maximal body pool of about _____, which can be maintained with intakes of 100-200 mg vitamin C per day.
a. 500 mg
b. 1000 mg
c. 1500 mg
d. 2000 mg
Q:
Vitamin C acts as a cofactor by maintaining iron in a reduced state in:
a. collagen synthesis.
b. methylation of homocysteine.
c. release of energy from nutrients.
d. red blood cell synthesis.
Q:
When ascorbic acid becomes dehydroascorbic acid it has _____.
a. lost 2 electrons
b. lost 1 electron
c. gained 2 electrons
d. gained 1 electron
Q:
Most animals synthesize their own ascorbic acid from _____.
a. glucose
b. glutamine
c. glycogen
d. alanine
Q:
A major function of B vitamins is to serve as:
a. antibodies.
b. a source of energy.
c. a part of a coenzyme.
d. electrolytes.
Q:
When water-soluble vitamins are consumed in excess of body needs, generally the excess is:
a. excreted in the feces.
b. stored in liver, bone, and adipose tissue.
c. excreted in the urine.
d. not absorbed.
Q:
Folic acid fortification has _____.a. not caused the decrease in NTDs that was expectedb. had no effect on the number of NTDs in this countryc. caused a greater decrease in NTDs than was expectedd. reduced the number of various NTDs by 11% to 50% in different studies
Q:
What is the criteria for a genetic difference to be called a "polymorphism"?a. It has to be lethal within 6 months of life.b. It causes a miscarriage 50% of the time.c. More men than women have the genetic difference.d. More than 1% of the population has the variation.
Q:
A genetic polymorphism that decreases the activity of N5,N10 methylene tetrahydrofolate reductase has been identified. This would cause _____.a. an accumulation of 5-methyl THFb. an increase in the homocysteine concentration in the cellc. a decreased risk for megaloblastic anemiad. a decreased risk for heart disease
Q:
How do we know that folate fortification has improved the biochemical folate status of Americans?a. more folate is being consumedb. Americans are more aware of folate's importancec. there is a decline in NTDsd. RBC folate levels have increased
Q:
Nutrients can be used to compensate for some gaps in our DNA. For example:a. Individuals with a change in the base sequence for the phenylalanine hydroxylase gene can correct the sequence of bases by eating a lot of phenylalanine.b. Obese individuals can lose body weight by eating fewer calories than they expend.c. Omega-3 fatty acids can up-regulate genes encoding for fat oxidation.d. Individuals with a polymorphism that decreases activity of a folate-metabolizing enzyme, methylene tetrahydrofolate reductase, may have more elevated plasma homocysteine than those with a normal enzyme while more folate intake can normalize plasma homocysteine for those with this polymorphism.
Q:
Describe the process by which vitamin B12 is digested and absorbed.
Q:
Explain the relationship of folate to vitamin B12 in the various anemias.
Q:
Discuss niacin equivalents and how they are calculated based on protein intake.
Q:
Sketch the Krebs cycle beginning with glycogen and show where various vitamin cofactors act in energy metabolism.
Q:
What is the significance of vitamin C to carnitine and fat metabolism?
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. Pick either posttranslational modification or allosteric regulation and provide one examplebe as specific as possible.
Q:
Folate and B12 have an important role in hematology ("blood-related" processes) such that a deficiency of either of these vitamins can result in anemia. Discuss the interrelationship between these vitamins and why a deficiency of either of them results in megaloblastic anemia. Your answer will likely need to talk to some extent about the methyl trap hypothesis. Make sure to relate any metabolic description of folate and B12 to the basis for anemia resulting from a deficiency.
Q:
Vitamins and Energy Metabolism. Vitamins play a big role in our ability to acquire energy from macronutrients. Pick one macronutrient and discuss how vitamins are involved in procuring energy; choose from: (1) carbohydrates (glycolysis/ TCA); (2) lipids (lipolysis/ β-oxidation); or (3) protein/ amino acids (gluconeogenesis). Your answer should be as specific as possible: names of vitamins and what they do with respect to the macronutrient you"ve chosen to help generate energy. A diagram may be especially useful.Hint: there are 4 vitamins for (1), 3-5 vitamins for (2), and 2-4 vitamins for (3)the range for (2) and (3) is because it depends on the FA or AA you start with.
Q:
One method to assess nutrient status is to measure the activity of an enzyme that requires the vitamin as a cofactor. Explain how this worksfirst in a conceptual way, and then specifically using an example. Your specific example choices are thiamin, riboflavin, or folate (pick one). Do you think this is a good assessment method? Why or why not?
Q:
One method to assess vitamin status is using a "load test." Explain how this worksfirst in a conceptual way, and then specifically using one example. Your specific example can be chosen from either tryptophan or histidine (pick one). Do you think this is a good assessment method? Why or why not?
Q:
For each vitamin listed below, indicate: (1) the active form of the vitamin, (2) the general function for the vitamin, and (3) an example of the general function (this could be a specific reaction or simply indicate a pathway/ process where it occurs). An example is provided; as you can see, your answers do not need to be long!Vitamins: Biotin, pantothenate, riboflavin, vitamin B6, thiamin, vitamin C, folateExample: Niacin(1) NAD(H) or NADP(H)(2) Oxidation-reduction reactions(3) TCA Cycle reaction or"¦.
Q:
The only test that will differentiate between a folic acid and cobalamin deficiency is the determination of the urinary metabolite _____, which is due to a lack of the coenzyme _____.
Q:
Pernicious anemia is identified by the _____ test, which involves using radioactive _____.
Q:
The continuation of the Kreb's cycle is ensured by the replenishment of oxaloacetate, which is formed by the carboxylation of _____ with a biotin-containing coenzyme, _____.
Q:
The digestion and absorption of cobalamin requires pepsin and _____; the presence of 2 nonenzymatic proteins: _____ and _____; and a receptor located in the _____.
Q:
Pharmacologic doses of 2 vitamins, _____ and _____, are used therapeutically to lower serum cholesterol and alleviate premenstrual syndrome, respectively.
Q:
Microcytic hypochromic anemia may result from a deficiency of the vitamin _____ because its coenzyme is involved in the synthesis of _____.
Q:
Match the nutrient listed to the phrase or word given. Nutrient choices may be used more than once.Associated Phrase1) hypochromic, microcytic anemia2) serine hydroxymethyltransferase3) edema and cardiac insufficiency4) hemoglobin synthesis5) prolyl hydroxylase6) Latin word means "leaf"; Italian word means "foliage"7) PLP is coenzyme form8) potatoes and broccoli are good sources9) coenzyme carries one-carbon groups in metabolism10) pernicious anemia is a lack of absorption of this11) gulonolactone oxidase12) coenzyme labilizes covalent bonds around the alpha-carbon of an amino acid13) UL = 2000 mg/d14) a water-soluble vitamin that is not a coenzyme15) a vitamin whose supplement form has MORE biologic action than the form found in natureNutrienta. vitamin B12b. vitamin B6c. folate or folic acidd. vitamin Ce. none of these
Q:
Match the coenzyme form of a vitamin with an enzyme and significant function.Coenzyme1) thiamin diphosphate2) flavin adenine dinucleotide3) nicotinamide adenine dinucleotide4) biotin5) pyridoxal phosphateEnzyme/Functiona. alanine aminotransferase; important in amino acid transaminations for facilitating protein synthesis b. pyruvate dehydrogenase; important for decarboxylations in carbohydrate catabolism c. glutathione reductase; important for red blood cell antioxidant integrity and a sensitive measure of riboflavin nutriture d. aldehyde dehydrogenase; important for catabolism of vitamin B6 (pyridoxal to pyridoxic acid) e. acetyl-CoA carboxylase; important to form malonyl-CoA and commit acetyl-CoA to fatty acid synthesis
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Vitamin C is a good reducing agent, meaning it keeps things reduced by undergoing irreversible oxidation; thus, it must continuously be replaced by dietary sources.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
In the folate-dependent one-carbon pool, a carbon unit in the methyl form (i.e., 5-methyl THF) is used in the conversion of homocysteine to methionine, whereas a carbon unit in the methylene form (i.e., 5,10-methylene THF) is used in DNA synthesis.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Biotin and B12 are both required for the synthesis of odd-chain fatty acids.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Urinary excretion of xanthurenic acid may be an indication of niacin deficiency.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
An increase in blood pyruvate and lactate levels may be due to a deficiency of riboflavin.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Circulating concentrations of a vitamin typically reflect diet, whereas intracellular (e.g., RBCs, leukocytes) concentrations reflect body pools.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
The reason we use equivalents when discussing the RDA for some vitamins is that there are different forms of the vitamin that, by weight, are not equal in terms of vitamin activitythis is due to differences in absorption and/or metabolism.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
High circulating levels of homocysteine (i.e., hyperhomocysteinemia) have been implicated in a number of pathologies including cardiovascular disease.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
The primary role of vitamin C is as a reducing agent, particularly for the mineral component of a number of enzymes that becomes oxidized following catalysis of a reaction.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
The active form of a vitamin is usually the form that has the greatest bioavailability.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Pernicious anemia can be due to folate or B12 deficiency.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Water-soluble vitamins are not stored, but readily excretedthe one exception is that we can store folate in the liver.
Q:
Indicate whether the statement is true or false. If the statement is false, explain why it is false.
Pellagra symptoms may appear during B6 deficiency, because this vitamin is required in the process of obtaining niacin from tryptophan.
Q:
PLP functions as a coenzyme for _____ when alanine enters the liver. Alanine becomes its -keto acid, _____.a. transamination, pyruvic acidb. transamination, -ketoglutaric acidc. transmethylation, histidined. desulfation, methioninie
Q:
B6-dependent transamination reactions are important in which process?
a. glyconeogenesis
b. gluconeogenesis
c. heme synthesis
d. more than one of the above
Q:
Ascorbic acid can reduce the oxidized form of vitamin E. Choose the phrase that describes this.
a. Ascorbic acid reduces the tocopheroxy radical to the quinone form; ascorbic acid is oxidized to dehydroascorbic acid.
b. Ascorbic acid reduces the hydroquinone form to the quinone form; ascorbic acid is reduced to semi-dehydroascorbic acid.
c. Ascorbic acid reduces the tochopheroxy radical to the tocopherol form; ascorbic acid is oxidized to semi-dehydroascorbate.
Q:
Which of the following vitamins has a Tolerable Upper Intake Level established?
a. thiamin
b. riboflavin
c. vitamin B6
d. vitamin B12
Q:
Because vitamin B6 is involved in heme synthesis, a deficiency symptom is
a. hypochromic, microcytic anemia.
b. seizures.
c. hyperhomocysteinemia.
d. impaired calcium metabolism.
Q:
Vitamin B6 functions importantly in all of the following EXCEPT _____.
a. transamination of amino acids
b. synthesis of fatty acids
c. synthesis of niacin
d. glycogen breakdown
Q:
A good source of vitamin B6 is muscle meats because PLP is predominantly bound to the enzyme _____.
a. alanine aminotransferase
b. cystathionine synthase
c. glycogen phosphorylase
d. aspartic aminotransferase
Q:
Metabolism of vitamin B6 to the primary coenzyme form, pyridoxal phosphate, requires the action of what other B vitamin?
a. GSH
b. NAD
c. THF
d. FMN
Q:
Which vitamin is most involved in amino acid metabolism?
a. biotin
b. vitamin E
c. vitamin A
d. vitamin B6
Q:
Large amounts of folic acid can mask a vitamin B12 deficiency and prevent _____ from resulting. Over time the symptoms unique to a vitamin B12 deficiency will occur, and these are related to the _____.
a. microcytic anemia, muscular system
b. DNA and RNA synthesis, vascular system
c. one-carbon transfer, nervous system
d. macrocytic anemia, nervous system
Q:
Which of the water-soluble vitamins is able to be stored and retained in the body for long periods of time?
a. folic acid
b. niacin
c. thiamin
d. B12
Q:
The normal digestion and absorption of cobalamin requires adequate protein digestion in the stomach; the presence of 2 nonenzymatic proteins: _____; and a receptor located in the _____.
a. R binders and hydrochloric acid, colon
b. pepsin and hydrochloric acid, ileum
c. R protein and intrinsic factor, ileum
d. R protein and intrinsic factor, duodenum
Q:
Vitamin B12 is absorbed in the _____.
a. duodenum
b. jejunum
c. ileum
d. colon
Q:
Intrinsic factor is required for the majority of absorption of which vitamin?
a. C
b. B6
c. B12
d. B2
Q:
What amount of supplemental folic acid is recommended daily for women of childbearing age in the United States?
a. 200 ug DFE
b. 400 ug DFE
c. 600 ug DFE
d. 800 ug DFE
Q:
Which of the following would you find under B12-deficient conditions and the methyl trap hypothesis?
a. accumulation of 5-methylene THF
b. depletion of homocysteine
c. accumulation of THF
d. accumulation of 5-methyl THF
e. more than one of the above
Q:
Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme _____.
a. folylpolyglutamate synthetase
b. dihydrofolate reductase
c. formimino glutamate
d. conjugase
Q:
Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of _____.
a. lipid bilayers
b. mitochondria
c. lysosomes and peroxisomes
d. purines and pyrimidines
Q:
Methionine is used to synthesize S-adenosylmethionine (SAM). Why is this important?
a. so that 5-methyl THF is formed
b. so that dUMP is catalyzed to dTMP
c. so that fatty acids with an odd-numbered chain can be metabolized
d. so that methyl groups are available
Q:
Elevated homocysteine levels can be due to all the following EXCEPT:
a. low ascorbic acid.
b. low folacin.
c. low cobalamin.
d. low pyridoxine.