Vitamins

Question 1

B1

Answer 1

thiamine: TPP

Question 2

B2

Answer 2

riboflavin: FAD, FMN

Question 3

B3

Answer 3

niacin: NAD+

Question 4

B5

Answer 4

pantothenic acid: CoA

Question 5

B6

Answer 5

pyridoxine: PLP

Question 6

B7

Answer 6

biotin

Question 7

B9

Answer 7

folate

Question 8

B12

Answer 8

cobalamin

Question 9

C

Answer 9

ascorbic acid

Question 10

fat soluble vitamins

Answer 10

A,D,E,K

Question 11

vit A (retinol)

Answer 11

• antioxidant
• visual pigments (retinal)
• normal diff of epith cells into specialized tissues
• prevents squamous metaplasia
• tx of measles, AML M3
• in liver (esp polar bears), leafy vegetables, beta-carotene (carrots)

Question 12

vit A (retinol) deficiency

Answer 12

• night blindness
• dry skin
• bitot spots (dry spots on conjunctiva)
• keratomalacia (wrinkling/clouding of cornea)
• xerophthalmia
• corneal ulcerations

Question 13

vit A (retinol) excess

Answer 13

• arthralgias, fatigue, HA, sore throat
• alopecia
• skin changes (oranging of skin, dry/pruritic skin)
• teratogenic (cleft palate, cardiac abnorm)
• increased ICP (pseudotumor cerebri)

Question 14

vit B1

Answer 14

• TPP = active form
• cofactor for enzymes in decarboxylation rxns (pyruvate DH, alpha-ketoglutarate DH, transketolase, branched-chain AA DH)

Question 15

vit B1 deficiency

Answer 15

• ATP depletion (from impaired glucose breakdown) –> WORSENED w/ glucose infusion
• brain/heart affected first (highly aerobic)
• Wernicke-Korsakoff synd
• Dry beriberi (neuritis, symm muscle wasting)
• Wet beriberi (high-output cardiac failure, dilated cardiomyopathy, edema)
• seen in alcoholics, in malnutrition, and in pts on dialysis

Question 16

vit B2

Answer 16

• cofactor in oxidation/reduction
• FAD (cofactor for succinate DH + component of ETC complex II)
• FMN (component of ETC complex I)

Question 17

vit B2 deficiency

Answer 17

• “mouth and eyes”
• cheilosis (inflamm of lips, scaling/fissures @ corners of mouth)
• corneal vascularization
• dermatitis
• stomatitis
• glossitis

Question 18

vit B3

Answer 18

• NAD+/NADP - used in redox rxns
• derived from tryptophan
• synth req B6 + B2

Question 19

vit B3 deficiency

Answer 19

• glossitis
• **pellagra: (if severe); aka caused by:
• Hartnup dz - decreased tryptophan absorp
• malig carcinoid synd (increased tryptophan metab)
• INH (decreases B6)

Question 20

vit B3 excess

Answer 20

facial flushing

Question 21

vit B5

Answer 21

-component of CoA + fatty acid synthase

Question 22

vit B5 deficiency

Answer 22

• dermatitis
• enteritis
• alopecia
• adrenal insuff

Question 23

vit B6

Answer 23

• pyridoxal phosphate = active form
• used in transamination (ALT, AST) and decarboxylation rxns
• cofactor for glycogen phosphorylase
• synth of cystathionine, heme, niacin, histamine, NT (serotonin, epinephrine, NE, GABA)

Question 24

vit B6 deficiency

Answer 24

• convulsions (bc decreased GABA)
• hyperirritability
• periph neuropathy (deficiency inducible by INH + oral contraceptives)
• sideroblastic anemias (due to impaired Hb synth and Fe excess) - bc lack of ALA-S enzyme

Question 25

best enzyme to test B1 deficiency?

Answer 25

transketolase

Question 26

"tea and toast" diet deficiency?

Answer 26

B3 (niacin)

Question 27

vit B2 impt for what enzymes?

Answer 27

- succinate DH (TCA) - fatty-acyl CoA DH (beta-oxidation) - glycerol phosphate shuttle

Question 28

B7 cofactor for?

Answer 28

carboxylation rxns: - pyruvate carboxylase (pyruvate (3C) --> OA (4C)) - used in gluconeogenesis - acetyl-CoA carboxylase (acetyl-CoA (2C) --> malonyl-CoA (3C)) - used in FA synthesis - propionyl-CoA carboxylase (propionyl-CoA (3C) --> methylmalonyl-CoA (4C)) - used to metabolize odd-chain FA, Val, Met, Ile, Thr ("VOMIT" pathway)

Question 29

B7 deficiency caused by? causes?

Answer 29

by avidin in egg whites or AB use | causes dermatitis, alopecia, enteritis; also fasting hypoglycemia (loss of pyruvate carboxylase)

Question 30

deficiency of B9 seen in?

Answer 30

alcoholics and pregnant pts | also w/ several drugs (phenytoin, sulfonamides, MTX, TMP)

Question 31

B9 function =?

Answer 31

converted to THF = coenzyme for 1C transfer/methylation rxns | impt for synth/repair of DNA and synth of nitrogenous bases in DNA + RNA

Question 32

B12 function?

Answer 32

cofactor for: - homocysteine methyltransferase (untraps inactive folate from storage [N5-methyl-THF]) - methylmalonyl-CoA mutase (part of "VOMIT" pathway)

Question 33

deficiency of vit B12 seen w/?

Answer 33

- malabsorption (enteritis, sprue, Diphyllobothrium latum) - lack of intrinsic factor - absence of terminal ileum (Crohn's disese)

Question 34

labs show what in B12 def?

Answer 34

increased methylmalonic acid and homocysteine levels

Question 35

SAM and methionine regen depend on?

Answer 35

vit B12 and folate

Question 36

4 functions of vit C?

Answer 36

- antioxidant - facilitate iron absorption by keeping in in reduced (Fe2+) state - nec for hydroxylation of proline and lysine in collagen synth - nec for dopamine-beta-hydroxylase (converts dopamine --> NE)

Question 37

vit D deficiency seen in patients that:

Answer 37

- breast feed | - have dark skin

Question 38

vit E function?

Answer 38

protect RBCs and membrane lipids from ROS

Question 39

vit E deficiency?

Answer 39

- hemolytic anemia (bc increased fragility of RBCs) - (proximal) muscle weakness - ***posterior column and spinocerebellar tract demyelination (mimics Friedrich's ataxia; ataxia, dysarthria, loss of proprioception/vibratory sense) - decrease serum phospholipids and cause infertility

Question 40

vit E tx for?

Answer 40

abetalipoproteinemia

Question 41

vit E excess?

Answer 41

``` hemorrhagic stroke (in adults) necrotizing enterocolitis (in infants) ```

Question 42

vit K function

Answer 42

gamma-carboxylation of glutamic acid residues (put another COO- group)

Question 43

vit K deficiency seen in pts that?

Answer 43

- breast feed | - after prolonged use of broad spectrum AB or phenytoin (wipe out intestinal gut flora)