Biochemistry-Nutrition

Question 1

thiamine

Answer 1

B1, TPP

Question 2

riboflavin

Answer 2

B2, FAD, FMN

Question 3

niacin

Answer 3

B3, NAD+

Question 4

pantothenic acid

Answer 4

B5, CoA

Question 5

pyridoxine

Answer 5

B6, PLP

Question 6

biotin

Answer 6

B7

Question 7

folate

Answer 7

B9

Question 8

cobalamin

Answer 8

B12

Question 9

ascorbic acid

Answer 9

VitC

Question 10

Vitamin A

Answer 10

differentiation of epithelial cells; prevents squamous metaplasia; used to treat measles, AML (M3)

Question 11

Vitamin A deficiency

Answer 11

night blindness, dry/scaly skin, alopecia, corneal degeneration, immune supression

Question 12

Vit A toxicity

Answer 12

arthralgias, scaly skin, cerebral edema, osteoporosis; teratogenic so need pregnancy test before starting isotretinoin for severe acne

Question 13

TPP is a cofactor for which reactions?

Answer 13

ATP: alpha-ketoglutarate dehydrogenase (TCA cycle); transketolase (HPM shunt in RBCs); pyruvate dehydrogenase (links glycolysis to TCA cycle; pyruvate to acetyl CoA); branched chain ketoacid dehydrogenase

Question 14

confusion, opthalmoplegia, ataxia + confabulation, etc

Answer 14

Wernicke Korsakoff syndrome–damage to medial dorsal nucleus of thalamus, mamillary bodies; make diagnosis by increased RBC transketolase activity after thiamine

Question 15

poylneuritis, synmmetrical muscle wasting

Answer 15

dry beriberi (thiamine deficiency)

Question 16

high output cardiac failure (dilated cardiomypathy); edema

Answer 16

wet beriberi (thiamine deficiency)

Question 17

B1 deficiency

Answer 17

impaired glucose breakdown, ATP depletion worsened by glucose infusion, if suspect, always give B1 first!

Question 18

What reaction in citric acid cycle uses vitamin B2?

Answer 18

B2–>riboflavin–>FAD/FMN–>succinate dehydrogenase (makes 2 ATP)

Question 19

B2 deficiency:

Answer 19

cheilosis, corneal vascularization

Question 20

What vitamins are needed to make B3?

Answer 20

B3 is niacin. tryptophan is precursor. Niacin synthesis requires B2 and B6.

Question 21

What causes B3 deficiency? Symptoms

Answer 21

Hartnup disease (decreased tryptophan absorption); malignant carcinoid (increased tryptophan use); isoniazid (decreased B6); Diarrhea, dementia, dermatitis

Question 22

Niacin overdose?

Answer 22

facial flushing (prostaglandin mediated) hyperglycemia, hyperuricemia

Question 23

Vitamin B5 deficiency

Answer 23

dermatitis, enteritis, alopecia, adrenal insufficiency

Question 24

What is B6 used for

Answer 24

converted to pyridoxal phosphate, cofactor used in transamination, decarboxylation reactions, glycogen phosphorylase, synthesis of cystathione, heme, niacin, histamine, and neurotransmitters (serotonin, epinephrine, norepinephrine, dopamine, GABA)

Question 25

B6 deficiency?

Answer 25

convulsions, hyperirratibility, peripheral neuropathy, sideroblastic anemias (impared hemeoglobin synthesis and iron excess)

Question 26

B7 is used for:

Answer 26

composes biotin, cofactor for carboxylation enzymes

Question 27

eating too many egg whites

Answer 27

B7 deficiency (avidin binds biotin)

Question 28

Use of B9?

Answer 28

converted to tetrahydrofolate (THF); 1-carbon transfer/methylation rxns; synthesis of nitrogenous bases

Question 29

What distinguishes B9 from B12 deficiency?

Answer 29

B12 has neurological symptoms, increased methymalonic acid levels

Question 30

Vitamin C

Answer 30

facilitates iron absorption by reducing it to Fe2+ states; necessary for hydroxylation of proline/lysine in collagen snthesis; necessary for dopamine B-hydroxylase to convert dopamine to NE

Question 31

hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination

Answer 31

Vit E deficiency--can appear similar to B12, but does not have megaloblastic anemia, hypersegmented neutrophils, or increased serum MMA levels