B vitamins

Question 1

What is vitamin B1? What is the main molecule where vitamin B1 is found?

Answer 1

thiamine thiamine pyrophosphate

Question 2

What is vitamin B2? What are the main two molecules that vitamin B2 is found?

Answer 2

riboflavin FAD and FMN

Question 3

What rare inherited defect in amino acid transport can cause a niacin deficiency?

Answer 3

Hartnup disease

• autosomal recessive defect in intestinal and renal transporters for neutral amino acids.
• This causes tryptophan excretion in urine and leads to pellagra

Question 4

Pt. with Diarrhea Dermatitis (classically in a “necklace” distribution around the neck) Dementia

Answer 4

Hartnup disease

Question 5

What 2 vitamins help synthesize Niacin?

Answer 5

Tryptophan + B2 and B6

Question 6

Pt is suspected of having thiamine deficiency. How can you confirm the Dx?

Answer 6

RBC transketolase activity will increase after the administration of thiamine

Question 7

Confusion, ophthalmoplegia, ataxia (classic triad) +confabulation, personality change, memory loss (permanent). What nucleus is damaged?

Answer 7

Wernicke-Korsakoff syndrome Damage to medial dorsal nucleus of thalamus, mammillary bodies

Question 8

Pt. suspected of having hypoglycemia. Treatment

Answer 8

give thiamine before dextrose to risk of precipitating Wernicke encephalopathy.

Question 9

polyneuropathy, symmetrical muscle wasting.

Answer 9

Dry beriberi

Question 10

Enzymes that require thymine (ATP)

Answer 10

α-ketoglutarate dehydrogenase (TCA cycle) Transketolase (HMP shunt) Pyruvate dehydrogenase (links glycolysis to TCA cycle) Branched-chain ketoacid dehydrogenase

Question 11

High-output cardiac failure (dilated cardiomyopathy)

Answer 11

Wet Beri Beri

Question 12

What type of cells are at risk of damage with B1 deficiency?

Answer 12

Highly aerobic cells are damaged first because they cannot generate ATP w/o thiamine

Question 13

Dermatomes affected in B3 difficiency

Answer 13

C3/C4

Question 14

The 2 C’sof B2 difficiencey

Answer 14

FAD and FMN (she has vitamin B2 deficiency manifesting as cheilosis and corneal vascularization)

Question 15

A 42 yo presents w/photophobia, inflamed lips, and fissures at the sides of her mouth. Which TCA cycle cofactors are deficient?

Answer 15

cheilosis and corneal vascularization Biotin: needed for carboxylation reactions

Question 16

What is Niacin used to treat? side effects?

Answer 16

Hyperlipidemia: lowers Hyperuricemia and hyperglycemia

Question 17

How can carcinoid syndrom cause pelegra?

Answer 17

Carcinoid syndrome is a complication of carcinoid tumors (most commonly of the small bowel) in which serotonin is systemically elaborated in great excess. Tryptophan is compensatorily shunted to make serotonin, decreasing conversion to niacin. Therefore, niacin deficiency is a potential complication of carcinoid syndrome.

Question 18

Gaba, Histamine and porphyrin/heme require what vitamin

Answer 18

B6

Question 19

Creatine, Urea, and Nitric oxide require which a.a.

Answer 19

Arginine

Question 20

only non water soluble B vitamin

Answer 20

B12 cobalomin in liver

Question 21

Which vitamin is needed for decarboxylation reactions and is also a cofactor for glycogen phosphorylase?

Answer 21

B6

Question 22

What parkinson drug therapy is decreased by vit b6 therapy

Answer 22

L-Dopa therapy vitamin B6 can convert L-DOPA to dopamine peripherally (as opposed to in the CNS), rendering treatment less efficacious.

Question 23

What complex of the electron transport chain is FMN and FAD part of.

Answer 23

Component of NADH dehydrogenase, aka complex I of the electron transport chain component of succinate dehydrogenase of the TCA cycle, aka complex II of the electron transport chain

Question 24

What vitamin is prevented from being absorbed by a certain protein in eggs?

Answer 24

Avidin… binds biotin

Question 25

Two etiologies that cause a vitamin deficiency and results in the following : Dermatitis Alopecia Enteritis Adrenal insufficiency

Answer 25

Biotin B7 antibiotic use or excessive consumption of raw egg whites

Question 26

Two etiologies that cause a vitamin diffieciecy and results in the following? Transamination Decarboxylation Glycogen phosphorylase

Answer 26

B6

Question 27

what 4 neurotransmitter synthesis reactions require B6

Answer 27

Glutamate → GABA Tryptophan → Serotonin DOPA → Dopamine (dopamine can then go on to form norepinephrine and epinephrine) Histidine → Histamine

Question 28

Vitamin needed for Co-enzyme A

Answer 28

B5

Question 29

Medications that can induce Vitamin B6 deficiency

Answer 29

include oral contraceptives and isoniazid.

Question 30

B6 is a precursor for what cofactor

Answer 30

PLP

Question 31

A 32 yo woman begins taking isoniazid after a TB Dx. Later, she develops numbness and tingling in her extremities. Dx?

Answer 31

B6 deficiency

Question 32

A man w/vitamin deficiency complains of fatigue, convulsions, hyperirritability, and peripheral neuropathy. Why is he experiencing fatigue?

Answer 32

He has sideroblastic anemia caused by vitamin B6 deficiency Microcytic

Question 33

Pt w/anemia has ringed sideroblasts on bone marrow biopsy. Which vitamin deficiency could cause this?

Answer 33

B6

Question 34

Which vitamin is required for the synthesis of an intermediate in the formation of cysteine?

Answer 34

B6--\> cystathionine Can lead to homocysteinuria