Vitamins

Question 1

Most common cause (MCC) of Biotin deficiency

Answer 1

excessive consumption of raw eggs (contain Avidin, a biotin-binding protein)

Question 2

MCC of Thiamine deficiency

Answer 2

alcoholism

Question 3

Alopecia, bowel inflammation, muscle pain

Answer 3

Biotin deficiency

Question 4

Wernicke (ataxia, nystagmus, ophthalmoplegia) - Korsakoff (confabulation psychosis)

Answer 4

Thiamine deficiency

Question 5

Beri-beri

Answer 5

Thiamine deficiency

Question 6

Enzymes requiring Biotin? Clue: “PAP carboxylases”

Answer 6

Pyruvate carboxylase (Gluconeogenesis), Acetyl CoA carboxylase (Fatty acid synthesis), Propionyl CoA carboxylase (Odd-carbon fatty acids, Val, Met, Ile, Thr)

Question 7

Enzymes requiring Thiamine? Clue: “PAB dehydrogenases + T”

Answer 7

Pyruvate DH (PDH pre-Krebs), Alpha-ketoglutarate DH (Krebs), Branched chain-ketoacid DH (Metabolism of Val, Iso, Leu), Transketolase (HMP shunt)

Question 8

Diarrhea, dementia, dermatitis, death - the 4 D’s of Niacin deficiency

Answer 8

Pellagra; Niacin is required by many dehydrogenases via NAD(H) or NADP(H)

Question 9

Deficiency in folic acid most common in

Answer 9

alcoholics, pregnant women (body stores depleted in 3 months)

Question 10

Enzyme requiring folic acid

Answer 10

Thymidylate synthase (in Thymidine pyrimidine synthesis)

Question 11

Diseases associated with folic acid deficiency

Answer 11

Homocystinemia (risk of DVT ad atherosclerosis), Megaloblastic anemia, Neural tube defects in fetus

Question 12

Enzymes requiring Cyanocobalamin (B12)

Answer 12

Homocysteine methyltransferase (Methionine, SAM), Methylmalonyl CoA mutase (Odd carbon fatty acids, Val, Met, Ile, Thr)

Question 13

Diseases associated with Cyanocobalamin deficiency

Answer 13

Pernicious anemia, Megaloblastic anemia, D. latum infection, Progressive peripheral neuropathy, terminal ileum resection, chronic pancreatitis, vegan diet

Question 14

MCC of Pyridoxine deficiency

Answer 14

Isoniazid therapy

Question 15

Enzymes requiring Pyridoxine

Answer 15

AST, ALT (Protein catabolism), Aminolevulinate synthase (Heme synthesis)

Question 16

Diseases associated with Pyridoxine deficiency

Answer 16

Sideroblastic anemia, Cheilosis or stomatitis, Convulsions

Question 17

Magenta-colored tongue, Corneal neovascularization, cheilosis or stomatitis

Answer 17

Riboflavin deficiency

Question 18

Enzymes requiring Ascorbate

Answer 18

Prolyl and lysyl hydroxylases (Collagen synthesis), Dopamine hydroxylases (Catecholamine synthesis)

Question 19

Painful glossitis, bleeding gums, easy bruising (perifollicular hemorrhage), poor wound healing, anemia

Answer 19

Scurvy (Vit. C deficiency), MCC: deficiency in diet

Question 20

Enzymes requiring Panthothenic acid/CoA

Answer 20

Fatty acid synthase and Fatty acyl Coa synthetase (Fatty acid metabolism), PDH, Alpha-ketoglutarate DH

Question 21

Rickets (children), Osteomalacia (adults)

Answer 21

Vit D deficiency

Question 22

Rate limiting enzyme in Vit D synthesis and activation, regulated by PTH

Answer 22

1alpha-hydroxylase in the proximal renal tubules

Question 23

Active form of Vitamin D

Answer 23

1,25-dehydroxycholecalciferol or “calcitriol”

Question 24

Drug class that inhibits osteoclast action (resorption of bone)

Answer 24

Bisphosphonates

Question 25

Teratogenic derivative of Vitamin A, used in the treatment of acne

Answer 25

Isotretinoin

Question 26

The three vitamin A structures difering on the functional group on carbon 1

Answer 26

retinol (-OH), retinoic acid (-COOH), retinal (-aldehyde)

Question 27

Family of proteins acting as Vitamin A intracellular receptors, regulating transcription via HREs

Answer 27

Zn-finger proteins

Question 28

Form of retinal involved in vision

Answer 28

cis-11-retinal, cofactor in converting opsin to rhodopsin (a 7-pass receptor coupled to the trimeric G protein “Transducin”, Gt)

Question 29

Light stimulation of rod cell causes (depolarization/hyperpolarization?)

Answer 29

Hyperpolarization. Light stops release of glutamate that is inhibiting the optic nerve bipolar cell = initiation of signal into the brain

Question 30

Bitot spots (conjunctival buildup of keratin debris), night blindness, follicular hyperkeratosis, alopecia

Answer 30

Vitamin A deficiency

Question 31

Acanthocytosis (increased acanthocytes/spur cells/spiculated RBCs), peripheral neuropathy, ataxia, retinitis pigmentosum

Answer 31

Vitamin E deficiency

Question 32

High blood levels of Vitamin E causes ____ in patients given Warfarin

Answer 32

Hemorrhage

Question 33

Factors II (prothrombin), VII, IX, X, and anticoagulant proteins C and S, require Vit K along with Ca in this process

Answer 33

Gamma-Carboxylation by Gamma-Glutamyl Carboxylase (cotranslational modification); this process is antagonized by Warfarin and Dicoumarol

Question 34

Bleeding time in Vit K and Vit C deficiency

Answer 34

Vit K: normal BT, Vit C: increased BT

Question 35

Prothrombin time in Vit K and Vit C deficiency

Answer 35

Vit K: increased PT, Vit C: normal PT

Question 36

Full anticoagulant activity by Warfarin and Dicoumarol (via inhibition of gamma-carboxylation) is seen after ___ days

Answer 36

2-3 days. Give Heparin (activator of antithrombin III) to provide short-term anticoagulation

Question 37

Only signaling molecule involved in the visual cycle of photoreceptor cells

Answer 37

CGMP phosphodiesterase (inactivates CGMP upon presence of Light)

Question 38

Anticonvulsant that decreases activity of Vitamin K

Answer 38

Phenytoin (phenyl hydantoins)