Reading 15

Question 1

tocopherols

Answer 1

Vitamin E class that has saturated side chains of 16 C

Question 2

tocotrienols

Answer 2

Vitamin E class that has unsaturated chains of 16 C

Question 3

What is the only tocopherol that has biological activity?

Answer 3

a-tocopherol; RRR tocopherol best stereoisomer;

Question 4

Sources of Vit E.

Answer 4

plant foods; specifically the oils from plants (wheat germ, sunflower. safflower,

Question 5

Factors that denature vitamin E

Answer 5

Prolonged exposure to air, sunlight, and heat.

Question 6

How are tocopherols present in foods?

Answer 6

Tocopherols are found free in foods, while tocotrienols and synthetic esters are found esterified and must be hydrolyzed before they can be absorbed.

Question 7

Where is vit E. absorbed?

Answer 7

Primarily in the jejunum by passive diffusion w/aid from bile acids

Question 8

What aids in the absorption of vitamin E?

Answer 8

Dietary lipids

Question 9

Vitamin E travel into the lymphatic tissue

Answer 9

Vitamin E travels into the enterocyte (apical side) within chylomicrons. ABCA1 on the basolateral membrane permits vitamin E to travel into the lymphatic fluid. Destination is the liver./

Question 10

What is the most prevalent form of Vitamin E in the blood? Why?

Answer 10

a-tocopherol. In the liver VLDL and aTTP aid in the distribution of alpha tocopherol to other tissues. It has specificity for alpha tocopherols.

Question 11

What tissue has the highest storage of vitamin E?

Answer 11

adipose tissue

Question 12

How is Vit. E uptaken in cells?

Answer 12

LDL and HDL receptors; ABCA1

Question 13

Quenching

Answer 13

the process by which vitamin E uses its free hydroxyl group in position 6 of its chromane ring

Question 14

What vitamin has the greatest ability to quench oxygen radicals?

Answer 14

Vitamin E, but only because it is in the greatest quantity in the solution

Question 15

What functional group of vitamin E provides hydrogen ions for free radicals?

Answer 15

The hydroxyl groups in the phenolic ring

Question 16

How is vitamin E regenerated after being oxidized?

Answer 16

By the action of reducing agents vitamin C, reduced glutathione, NADPH, ubiquinol or dihydrolipoic acid

Question 17

What genes are transcriptionally controlled by vitamin E?

Answer 17

steroidogenesis, lipid uptake, antioxidant defense, the cell cycle, inflammation, cell adhesion, and blood coagulation

Question 18

What cell membrane receptor does vitamin E inhibit?

Answer 18

inhibits protein kinase C, functions in the transduction of signals from G protein signals

Question 19

Tocotrienols Suppress activity of _____

Answer 19

HMG-CoA reductase in cholesterol synthesis

Question 20

What nutrients have a complementary relationship with vitamin E?

Answer 20

Selenium and Vitamin C

Question 21

What nutrient uptake does vitamin E inhibit?

Answer 21

b-carotene; and vitamin K

Question 22

Naturally occurring forms of Vitamin K

Answer 22

Phylloquinone (Vitamin K1); Menaquinone (Vitamin K2)

Question 23

What is the most uptaken form of Vitamin K?

Answer 23

phylloquinones

Question 24

What are some sources of vitamin K?

Answer 24

Plant foods; leafy vegetables, collards, spinach, turnip greens, some salad greens, and broccoli .

Question 25

What form of vitamin K is synthesized by bacterial in the intestines?

Answer 25

Menaquinones, but they do not provide a sufficient amount of Vitamin K to meet the body’s needs

Question 26

Phylloquinone absorption

Answer 26

Phylloquinones require no digestion; absorbed in the jejunum as a part of micells; also can be absorbed by passive transport in the duodenum and jejunum

Question 27

Menaquinone absorption

Answer 27

absorbed by passive diffusion from the ileum and colon

Question 28

Where is vitamin K stored

Answer 28

In cell membranes of (lungs, kidneys, bone marrow, and adrenal glands)

Question 29

What is the primary function of Vitamin K?

Answer 29

postranslational carboxylation of specific glutamic acid residues in proteins (forms g-carboxyglutamic acid)

Question 30

Function of Vitamin K

Answer 30

blood clotting, bone mineralization, apoptosis, growth, and signal transduction

Question 31

Thrombin

Answer 31

Catalyzes the proteolysis of fibrinogen to yield fibrin.

Question 32

What enzyme is responsible for carboxylation of glutamic acid residues on proteins?

Answer 32

Vitamin K dependent g-glutamyl carboxylase; associated with the rough ER

Question 33

What function do carboxylated Gla residues play?

Answer 33

The bind calcium, which causes Gla proteins to bind to negatively charged phospholipids on membrane surfaces or blood platelets and endothelial cells at the site of injury

Question 34

Vitamin K cycle

Answer 34

1) Vit. K reduced to KH2 by quinone reductase 2)KH2 O2 and CO2 along with vit. K dependent g-glutamyl carboxylase carboxylate glutamic acid 3) Vit. K 2,3 epoxide formed 4) Vit. K 2,3 epoxide converted back to Vit K by epoxide reductase.

Question 35

Anticoagulants

Answer 35

Function by inhibiting epoxide reductase, thus limiting vit. K production

Question 36

What vitamins antagonize Vitamin K?

Answer 36

Vitamin E and A

Question 37

Side effects of Vit. K deficiency

Answer 37

Hemorrhage; diminish bone mineral density; increased fracture rates.