Wk1 Fat soluble vit/minerals/elect pt 1

Question 1

Define EAR (Estimated Average Requirement)

Answer 1

Average daily nutrient intake level estimated to meet the requirements of of half of the healthy members of a particular life stage and gender group

Question 2

Define RDA (Recommended Daily Allowance)

Answer 2

Average daily dietary nutrient intake level sufficient to meet the nutritional requirements of nearly all (97-98%) healthy persons in a particular life stage and gender group

Question 3

Define Tolerable Upper Limit:

Answer 3

Risk of “overdose” is approx. 0.1%

Question 4

Biologically active form of vit A:

Answer 4

all-trans-retinol

• B-ionone ring
• branched polyunsaturated acyle chain
• alcohol

Question 5

Three things all-trans-retinol can be converted to:

Answer 5

1. aldehyde
2. carboxylic acid
3. ester w/ fatty acid (eg. palmitate)

Question 6

Three dietary forms of vit A:

Answer 6

1. retinyl palmitate
2. B-carotene
3. a-carotene

Question 7

Vit A metabolite that can be transported in blood with albumin:

Answer 7

Retinoic acid

Question 8

Vit A metabolites that are transported in chylomicrons:

Answer 8

Retinyl-fatty acid esters

Question 9

Reservoir for vit A storage in liver:

Answer 9

Stellate cells

Question 10

retinal cycle in photoreceptors?

Answer 10

cis-retinal + opsin = rhodopsin

rhodopsin + UV light = opsin + tras-retinal

trans-retinal –> G-protein rec. –> closes Na+ channels –> hyperpolarization of rod cell –> signals neuron

trans-retinal recycled back to cis-retinal

Question 11

4 roles of retinoic acid ligand based transcription factors (RAR, RXR, PPAR):

Answer 11

1. differentiation of goblet cells (inhibits keratinization)
2. apoptosis of cancer cells
3. maturation of dendritic cells
4. recruitment of antibody secreting cells to small intestine

Question 12

Vit A metabolites that act as antioxidants:

Answer 12

carotenes (double bonds bind free radicals)

Question 13

Bitot’s spots in the eye?

Answer 13

Vit A deficiency

Question 14

Dry eye due to keratinization?

Answer 14

xeropthalmia

due to vit A deficiency

Question 15

Vit E form with SATURATED 16-C acyl chains:

Answer 15

tocopherols

Question 16

Vit E form with polyUNsaturated 16-C acyl chains:

Answer 16

tocotrienols

Question 17

Vit E absorption and distribution parallels _____?

Answer 17

fat digestion and absorption

Question 18

Vit E functions?

Answer 18

1. lipid bilayers
2. intracellular plasma membranes
3. cellular oxidative stress defense

Question 19

Vit that can inhibit Vit K absorption and metabolism:

Answer 19

Vit E

Question 20

Vit E deficiency: Causes? Symptoms?

Answer 20

Causes:

• premature infants
• Crohns
• short bowel syndrome

Sx:

• myopathy
• hemolytic anemia
• peripheral neuropathy
• ataxia, loss of vibratory sense

Question 21

Main form of dietary vit K:

Answer 21

Phylloquinone

green leafy vegetables

Question 22

Vit K produced by fermentation:

Answer 22

Menaquinones

Question 23

Vit K absorption paralells _____.

Answer 23

fat

Question 24

Vit K stored in _______.

Answer 24

cell membranes of lung, kidney, bone marrow, adrenal glands

Question 25

Coumadin blocks what enzyme?

Answer 25

vit k epoxide reductase **increases PTT

Question 26

Clotting factors reliant on vit K dependent carboxylation:

Answer 26

VIIa IX X

Question 27

Main circulating form of vit D:

Answer 27

25-hydroxycholecalciferol

Question 28

Biologically active form of vit D:

Answer 28

1,25-dihydrocholecalciferol

Question 29

Where does vit D get activated:

Answer 29

kidney **in response to PTH

Question 30

Enzyme in kidney responsible for activating vit D:

Answer 30

1-a-hydroxylase (+ PTH)

Question 31

Ca++ channel on brush border:

Answer 31

TRPV6

Question 32

Vit D deficiency characterized by seizures, growth retardation, failure of bone mineralization (osteomalacia):

Answer 32

rickets

Question 33

Most toxic vitamin?

Answer 33

D

Question 34

Vit associated with reduced colorectal carcinoma:

Answer 34

vit D

Question 35

Most abundant metal ion in the body:

Answer 35

Calcium

Question 36

HOw does Ca++ get across basolateral membrane?

Answer 36

Ca++ ATPase

Question 37

Transcellular movement of Ca is regulated by?

Answer 37

calcitrol

Question 38

Pericellular transport of Ca is regulated by?

Answer 38

Claudin

Question 39

Inhibits PTH?

Answer 39

calcitonin

Question 40

Intracellular signalling by calcium is mediated by?

Answer 40

calmodulin

Question 41

How does Ca decrease cholesterol?

Answer 41

traps bile salts and fatty acids in undigestable soaps --> diverts cholesterol to bile salt synthesis

Question 42

Saturable transport of Mg+ across brush border?

Answer 42

TRPM6

Question 43

Basolateral transport of Mg+?

Answer 43

1. 2Na+ / Mg2+ antiporter | 2. 2K+ / 3Na+ ATPase (creates favorable Na conc for #1 above)

Question 44

Functions of Mg++?

Answer 44

bone ATP kinases polymerases

Question 45

Best measurement of Mg++?

Answer 45

renal excretion

Question 46

SLC12A3 mutation

Answer 46

Gitelman Syndrome

Question 47

Intracellular processes dependent on Mg++:

Answer 47

ATP associated processes