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24 Cards in this Set
- Front
- Back
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what form do B vits need to be in for absorption and transport in blood? |
free form |
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what is the distinguishing feature of thiamin? how does its structure change when being converted to coenzyme form? |
2 rings, connected by methyline bridge
S containing ring |
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what is the distinguishing feature of riboflavin? how does its structure change when being converted to coenzyme form? |
3 ring structure, 5C sugar
coenzymes = FMN FAD
flavin mononucleotide- phosphate is added flavin adenine dinucleotide- nucleotide and extra phosphate are added |
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what is the distinguishing feature of niacin? how does its structure change when being converted to coenzyme form? |
niacin is an N containing ring with either an acid or an amide
NAD+ NADPH
Nicotinamide adenine dinucleotide Nicotinamide adenine dinucleotide phosphate
5 C sugars and phosphates are added
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2 functions of TPP? |
energy metabolism, synthesis of pentoses and NADPH
(involved in transfer of 2C gps)
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FMN and FAD are coenzymes for multiple enzymes provide an example |
FAD in a coenzyme for succinate dehydrogenase in TCA cycle
FAD is coenzyme for beta oxidation
both result in FADH which can regenerate FAD+ in the electron transport chain |
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what is the function of NAD+
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oxidising agent |
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what is the function of NADPH? |
reductive biosynthesis, associates with glutathione reductase |
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what nutrients are added to soy milk products? |
B2, B12, calcium |
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main food sources for it B1, B2, B3 |
B1- cereal products B2- dairy B3- meat |
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how is vitamin B1 status tested? |
transketolase activity test, with/without TPP
if activity of transketolase enzyme increases with added TPP = deficient |
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what 2 vitamins have similar deficiency diseases? |
B2, B3
ariboflavinosis pellagra
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what are the symptoms of pellagra? |
dementia, diahhreoa, dermatitus |
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what is the specific test for B2 nutritional status? |
erythrocyte glutathione reductase activity (as FAD is cofactor |
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what vitamin has a similar nutritional status test to B1? |
B6 activity of erythrocyte alanine amino transferase with/ without PLP |
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what is the relationship between tryptophan and niacin? |
fasting plasma tryptophan = def of B3
means tryptophan is not being utilised to make niacin |
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how many of and were are the transporters for B1 and B2? |
2 types, small and large intestine |
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if consuming a low CHO diet, how does this affect thiamin transporters? how does this compare to a low riboflavin diets affect on transporters? |
low CHO = low thiamin = more transporters
low riboflavin = less transporters |
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what nutrients does excessive chronic alcoholism have an impact on |
thiamin- decreases expression of thiamin transporter
folate- inhibits conjugase activity, reduces gene expression for RFC therefore affects B12 potentially |
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for facilitated diffusion into plasma of B vitamins, how is the concentration gradient maintained? |
broken down, absorbed as free it reassembled as coenz in enterocyte broken down again for export |
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water soluble vitamins are 'generally' excreted in the urine, fat sol in the bile. What is an exception to this rule? |
vitamin A- if conjugated it is realised in the bille, if oxidised (made water sol) released in urine
folate- released into bile, if not reabsorbed then is lost, if catabolised excreted in the urine |
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what are the 3 aspects of deficiency biochemical tests can test for? |
reduced intake, reduced storage, reduced function |
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provide an example of the 3 levels of testing in relation to thiamin |
intake- urinary levels of unmetabolised thiamin
storage- RBD thiamin
function- transketolase activity with/ without TPP |
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what are the 4 nutrients with equivalence units? |
Vitamin A (RE) Fibre (DFE) Vit E (a-TE) B3- NE |
