Deck 43: Vitamins

Question 1

The in-vivo synthesis of the active form of vitamin D begins with 7-dehydrocholesterol being converted to cholecalciferol in the ______.Cholecalciferol is next hydroxylated in the ______, followed by a second hydroxylation in the ______ to form 1,25-dihydroxycholecalciferol.

A)liver, kidney, skin
B)skin, liver, kidney
C)kidney, liver, skin
D)skin, kidney, liver

Answer 1

skin, liver, kidney

Question 2

The major function(s) of water-soluble vitamins in the body is/are:

A)as sources of energy
B)as coenzymes
C)as acute-phase reactants
D)all of the above

Answer 2

as coenzymes

Question 3

Which vitamin is known chemically as pyridoxine?

A)vitamin B₁
B)vitamin B₂
C)vitamin B₃
D)vitamin B₆

Answer 3

vitamin B₆

Question 4

Wernicke-Korsakoff syndrome is commonly seen in ______ and is associated with a ______ deficiency.

A)pellagra, niacin
B)alcoholism, thiamine
C)wet beriberi, carnitine
D)rickets, vitamin D

Question 5

Which of the following statements are true of vitamin B₃?
1)It is readily absorbed in the gut.
2)It is completely dependent on diet for a direct source.
3)There is abundant storage of B₃ in the body.
4)Urine contains nicotinamide and other metabolites of B₃.

A)1, 3, 4
B)2, 3, 4
C)1, 2
D)3, 4

Question 6

What vitamin is consistent with the following characteristics?
1)Foods high in this vitamin include milk, liver, eggs, meat, and some green, leafy vegetables.
2)This vitamin is a highly pigmented yellow compound that consists of flavin.
3)A deficiency can cause mouth lesions, glossitis, photophobia, eyelid spasm, and neurological alterations.

A)vitamin B₁
B)vitamin B₂
C)vitamin B₃
D)vitamin B₆

Question 7

The active form of vitamin K is important in which of the following steps of the coagulation pathway?

A)the conversion of glutamic acid to delta-carboxyglutamic acid
B)the binding of calcium
C)the formation of an ionic bridge for clot formation
D)the binding with phospholipids

Question 8

Biotin acts as a coenzyme that participates in which metabolic pathway?
1)gluconeogenesis
2)fatty acid synthesis
3)amino acid catabolism

A)1, 2, 3
B)1, 2
C)1, 3
D)2, 3

Question 9

Which of the following statements are true regarding the laboratory analysis of vitamin status?
1)Measurement of urinary metabolites of a vitamin is one approach utilized for determining vitamin status.
2)Measurement of a biochemical function requiring the vitamin, with and without in-vitro addition of the cofactor form, is one approach utilized for determining vitamin status.
3)Detection of reduced serum concentrations of a vitamin is utilized to indicate a deficiency that interrupts cellular function.
4)Detection of vitamin values within a reference interval defined by population studies is utilized to indicate an adequate supply of that vitamin.

A)1, 2, 3, 4
B)2, 3, 4
C)3, 4
D)1, 2

Question 10

It is reasonable to expect a request for the laboratory analysis of fat-soluble vitamins in which of the following conditions?

A)pancreatic insufficiency
B)alcoholic liver disease
C)presence of steatorrhea
D)all of the above

Question 11

Hemolytic anemia may be associated with which vitamin deficiency?

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

Question 12

Considering characteristics of lipid-soluble vitamins, ______ can be stored in liver parenchymal cells for a year or longer, ______ can be stored in body fat for several months, and ______ appears to only be stored for a period of days or weeks.

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

Question 13

Absolute vitamin deficiencies can be the result of:
1)a nutritional deficit
2)an inability to properly absorb a vitamin
3)an increased metabolism and clearance
4)a markedly increased utilization

A)1, 2, 3, 4
B)1, 2, 4
C)1, 2, 3
D)2, 3, 4

Question 14

Which of the following statements are true of the major forms of vitamin K?
1)The phylloquinone form of vitamin K is found in fruits.
2)The phylloquinone form of vitamin K constitutes the dietary source of vitamin K.
3)The menaquinone form of vitamin K is produced in gram-negative bacteria.
4)The menaquinone form of vitamin K represents the bowel-derived source of vitamin K.

A)1, 3
B)1, 4
C)2, 3
D)2, 4

Question 15

Vitamin A toxicity:

A)can occur as a result of overmedication with vitamin supplements.
B)can result from the use of topical retinoids for acne.
C)can cause dry skin, bone pain, fatigue, and renal disorders.
D)all of the above

Question 16

Vitamin B₁₂ is usually measured in the laboratory at the same time as which other vitamin, owing to their clinical similarities of deficiency and metabolic interactions?

A)thiamine
B)niacin
C)folic acid
D)carnitine

Question 17

In the general comparison of fat-soluble and water-soluble vitamins, ______ vitamins are generally expected to be stored longer in the body, and a deficiency of ______ vitamins may develop in a short period of time.

A)fat-soluble, fat soluble
B)fat-soluble, water-soluble
C)water-soluble, fat-soluble
D)water-soluble, water-soluble

Question 18

The need for laboratory evaluation of vitamin E status may be indicated by which of the following diets?

A)a diet high in vegetable oils
B)a diet high in fresh, green vegetables
C)a diet high in unsaturated fats
D)a diet low in unsaturated fats