Chapter 9: Fat-soluble Vitamins (Vitamin A)

Question 1

other names

retinoic acid
retinal
retinol
dehydroretinol
anti-infective vitamin

Answer 1

vitamin a

Question 2

vitamin a - chemistry

stable to _____ (ordinary cooking temp), _____, and _____

Answer 2

heat, acid, alkali

Question 3

vitamin a - chemistry

destroyed by _____ and _____ (when become rancid) or light

Answer 3

oxidation and destruction

Question 4

vitamin a - chemistry

exists in 3 forms that are found in animal tissues

Answer 4

retinol, retinal, or retinaldehyde and reitnoic acid

Question 5

vitamin a - chemistry

are formed when retinol combines with an organis acid

Answer 5

retinyl esters

Question 6

vitamin a - chemistry

retinyl esters, retinol, and retinal are incovertible; all forms can be converted to retinol acid, a “_____”

Answer 6

terminal product

Question 7

vitamin a - chemistry

are precursors of vitamin a and occur in 2 structural forms

Answer 7

carotenes

Question 8

vitamin a - chemistry

carotenes occur in 2 structural forms that are present in plants (as provitamin, carotenoid precursor)

Answer 8

alpha carotene and beta carotene

Question 9

vitamin a - chemistry

can undergo oxidative cleavage to 2 molecules of retinol

Answer 9

beta carotene

Question 10

vitamin a - chemistry

_____ refers to a biologically active form. found in the animal foods

Answer 10

retinol esters

Question 11

vitamin a - chemistry

_____ is the unit of measure

Answer 11

retinol equivalent (re)

Question 12

vitamin a - chemistry

_____ and united states pharmacopeia units are used to measure vitamin a activity

Answer 12

international units (iu)

Question 13

vitamin a - chemistry

RE = 1 ug retinol (_____ IU)

Answer 13

3.33

Question 14

vitamin a - chemistry

1 RE = _____ beta carotene (10 IU)

Answer 14

6 ug

Question 15

vitamin a - chemistry

1 RE = _____ other carotenoids

Answer 15

12 ug

Question 16

vitamin a - absorption, transport, and utilization

_____ and _____ are the preformed vitamin a (easily absorbed) because it can be metabolized directly into compounds that exert biological effect of vitamin a

Answer 16

retinol and retinyl esters

Question 17

vitamin a - absorption, transport, and utilization

are produced only by plants, and they function as accessory light-gathering pigments that enhance photosynthesis efficiency

Answer 17

carotenoids

Question 18

vitamin a - absorption, transport, and utilization

carotenoids are the common dietary source, however, they are absorbed at much _____ rates

Answer 18

slower rates

Question 19

vitamin a - absorption, transport, and utilization

retinol from food can be absorbed as such by the _____

Answer 19

intestinal wall cells

Question 20

vitamin a - absorption, transport, and utilization

are hydrolyzed to free retinol and an organic acid

Answer 20

retinyl esters

Question 21

vitamin a - absorption, transport, and utilization

absorption if facilitated by

Answer 21

bile

Question 22

vitamin a - absorption, transport, and utilization

_____ carotene are needed to produce the vitamin a activity of 1 ug retinol

Answer 22

6 ug

Question 23

vitamin a - absorption, transport, and utilization

is the predominant retinyl ester in food

Answer 23

retinyl palmate

Question 24

_____% of performed dietary vitamin a is absorbed

Answer 24

75%

Question 25

vitamin a - absorption, transport, and utilization

dietary beta carotene and other carotenoids, _____ is absorbed

Answer 25

5-50%

Question 26

vitamin a - absorption, transport, and utilization

stored in the _____ (90%) and _____

Answer 26

liver; adipose tissue

Question 27

vitamin a - absorption, transport, and utilization

incorporated into the _____ for transport through the _____

Answer 27

chylomicrons; lymphatic system

Question 28

vitamin a - absorption, transport, and utilization

cellular RBP and cellular retinoic acid-binding protein attach to retinol and retinoic acid, respectively; transfer to cell nucleus where they can effect gene expression

Answer 28

intracellular retinol-binding proteins

Question 29

vitamin a - absorption, transport, and utilization

storage of vitamin a occurs in the liver as _____

Answer 29

retinyl ester

Question 30

vitamin a - absorption, transport, and utilization

when in need, it is released from the liver, transported to the blood by forming a complex with a transport protein called _____

Answer 30

RBP

Question 31

vitamin a - absorption, transport, and utilization

the conversion of retinol to retinoic acid is _____

Answer 31

irreversible