FNDH 620 ACTUAL EXAM STUDY GUIDE QUESTIONS AND
ANSWERS SURE A+
✔✔Forms of Thiamin (B1) - ✔✔thiamin diphosphate (TDP) and active form thiamin
triphosphate (TPP)
✔✔Sources of thiamin - ✔✔enriched grains, pork, nuts
✔✔At low concentration B1 is absorbed into enterocyte - ✔✔via Na+/K+ pump
✔✔At high concentration B1 is absorbed into enterocyte - ✔✔via passive diffusion
✔✔What happens to B1 in the liver? - ✔✔ATP donates a phosphate to TDP -> TPP and
then circulated to extrahepatic tissues
✔✔Where is about 50% of B1 stored in the body? - ✔✔The muscle
✔✔B1 excretion - ✔✔Urine: reported more than 50 metabolites
✔✔Thiamin/B1 function - ✔✔- coenzyme for decarboxylation reactions in CHO
catabolism
- important for ATP synthesis and acetyl-CoA production -> synthesis of FAs, ketone
bodies, cholesterol
- coenzyme for transketolase in the pentose phosphate pathway (means of generating
NADPH for FA synthesis)
✔✔Thiamin Deficiency - ✔✔Beriberi (wet: heart failure/dry: muscle weakness)
✔✔Riboflavin (B2) sources - ✔✔dairy products, meats, eggs, leafy greens, mushrooms
fortified cereal
✔✔Brain cells uptake: - ✔✔FAD through high-affinity transport system so FAD in brain
does not decline during deficiency
✔✔Urinary excretion of flavus: - ✔✔reflects dietary intake and is a biomarker used in
intervention studies (yellow color)
✔✔B2 deficiency - ✔✔cheilosis; glossitis; corneal vascularity
✔✔PQ: T/F Nicotinamide, but not nicotinic acid, is the form required for the synthesis of
nicotinamide adenine dinucleotide. - ✔✔False
✔✔PQ: How are recommended intakes of niacin expressed (units)? - ✔✔Niacin
equivalents
, ✔✔PQ: List 4 water-soluble vitamins that are required by pyruvate dehydrogenase
complex. - ✔✔Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5)
✔✔How many mg of tryptophan = 1 mg niacin? - ✔✔60 mg tryptophan = 1 mg niacin
(niacin equivalent)
✔✔Niacin (B3) sources - ✔✔Liver, nuts, legumes
✔✔Why is niacin is some plant foods on 10-30% bioavailable? - ✔✔Bound to
CHO/peptides
Corn: low in tryptophan
Sorghum: high levels of leucine inhibits niacin synthesis from tryptophan
✔✔Niacin absorption at low concentratins - ✔✔via Na+ dependent pumps
✔✔Niacin absorption at high concentrations - ✔✔via passive diffusion
✔✔PQ: T/F Absorption of biotin is near 0% from wheat. - ✔✔True
✔✔What is corn's bioavailability of biotin? - ✔✔100%
✔✔What was biotin once referred to as? - ✔✔Vitamin H
✔✔What is biotin usually bound to? - ✔✔A protein called biocytin or biotinllysine
✔✔Why might eggs cause a deficiency of biotin? - ✔✔The protein avidin in eggs binds
to biotin inhibiting intestinal absorption
✔✔T/F Intestinal flora produces a small amount of biotin. - ✔✔True
✔✔What percent of biotin is free in the blood? - ✔✔80%
✔✔How might IBD cause deficiency of biotin? - ✔✔Inflammation of intestinal system
and GI tract inhibits bacterium growth, thus inhibiting synthesis of biotin.
✔✔PQ: Intake of raw egg white might cause deficiency of - ✔✔biotin
✔✔What are the 6 forms of B6? - ✔✔Pyridoxal Phosphate (PLP): active form
Pyridoxine (PN)/ Pyridoxine Phosphate (PNP): found in plant foods
Pyridoxal (PL)/Pyridoxamine (PM): phosphorylated form found in animal product
✔✔Food sources of B6 (Pyridoxine) - ✔✔meat, poultry, fish, fortified cereal, starchy
vegetables, noncitrus fruits and juices
ANSWERS SURE A+
✔✔Forms of Thiamin (B1) - ✔✔thiamin diphosphate (TDP) and active form thiamin
triphosphate (TPP)
✔✔Sources of thiamin - ✔✔enriched grains, pork, nuts
✔✔At low concentration B1 is absorbed into enterocyte - ✔✔via Na+/K+ pump
✔✔At high concentration B1 is absorbed into enterocyte - ✔✔via passive diffusion
✔✔What happens to B1 in the liver? - ✔✔ATP donates a phosphate to TDP -> TPP and
then circulated to extrahepatic tissues
✔✔Where is about 50% of B1 stored in the body? - ✔✔The muscle
✔✔B1 excretion - ✔✔Urine: reported more than 50 metabolites
✔✔Thiamin/B1 function - ✔✔- coenzyme for decarboxylation reactions in CHO
catabolism
- important for ATP synthesis and acetyl-CoA production -> synthesis of FAs, ketone
bodies, cholesterol
- coenzyme for transketolase in the pentose phosphate pathway (means of generating
NADPH for FA synthesis)
✔✔Thiamin Deficiency - ✔✔Beriberi (wet: heart failure/dry: muscle weakness)
✔✔Riboflavin (B2) sources - ✔✔dairy products, meats, eggs, leafy greens, mushrooms
fortified cereal
✔✔Brain cells uptake: - ✔✔FAD through high-affinity transport system so FAD in brain
does not decline during deficiency
✔✔Urinary excretion of flavus: - ✔✔reflects dietary intake and is a biomarker used in
intervention studies (yellow color)
✔✔B2 deficiency - ✔✔cheilosis; glossitis; corneal vascularity
✔✔PQ: T/F Nicotinamide, but not nicotinic acid, is the form required for the synthesis of
nicotinamide adenine dinucleotide. - ✔✔False
✔✔PQ: How are recommended intakes of niacin expressed (units)? - ✔✔Niacin
equivalents
, ✔✔PQ: List 4 water-soluble vitamins that are required by pyruvate dehydrogenase
complex. - ✔✔Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5)
✔✔How many mg of tryptophan = 1 mg niacin? - ✔✔60 mg tryptophan = 1 mg niacin
(niacin equivalent)
✔✔Niacin (B3) sources - ✔✔Liver, nuts, legumes
✔✔Why is niacin is some plant foods on 10-30% bioavailable? - ✔✔Bound to
CHO/peptides
Corn: low in tryptophan
Sorghum: high levels of leucine inhibits niacin synthesis from tryptophan
✔✔Niacin absorption at low concentratins - ✔✔via Na+ dependent pumps
✔✔Niacin absorption at high concentrations - ✔✔via passive diffusion
✔✔PQ: T/F Absorption of biotin is near 0% from wheat. - ✔✔True
✔✔What is corn's bioavailability of biotin? - ✔✔100%
✔✔What was biotin once referred to as? - ✔✔Vitamin H
✔✔What is biotin usually bound to? - ✔✔A protein called biocytin or biotinllysine
✔✔Why might eggs cause a deficiency of biotin? - ✔✔The protein avidin in eggs binds
to biotin inhibiting intestinal absorption
✔✔T/F Intestinal flora produces a small amount of biotin. - ✔✔True
✔✔What percent of biotin is free in the blood? - ✔✔80%
✔✔How might IBD cause deficiency of biotin? - ✔✔Inflammation of intestinal system
and GI tract inhibits bacterium growth, thus inhibiting synthesis of biotin.
✔✔PQ: Intake of raw egg white might cause deficiency of - ✔✔biotin
✔✔What are the 6 forms of B6? - ✔✔Pyridoxal Phosphate (PLP): active form
Pyridoxine (PN)/ Pyridoxine Phosphate (PNP): found in plant foods
Pyridoxal (PL)/Pyridoxamine (PM): phosphorylated form found in animal product
✔✔Food sources of B6 (Pyridoxine) - ✔✔meat, poultry, fish, fortified cereal, starchy
vegetables, noncitrus fruits and juices
