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31 Cards in this Set
- Front
- Back
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What part of the thiamin structure is most susceptible to breaking?
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the methylene bridge
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What source is unique to providing alot of thiamin?
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pork
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What form is thiamin found in animal products?
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phosphorylated form
*TDP / TPP |
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What form is thiamin found in plants?
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Free form
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In what form is thiamin absorbed into the enterocyte?
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free thiamin
* phosphorylated forms must be digested first |
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Where are the unphosphorylated and phosphorylated forms of thiamin found in the body?
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unphosphorylated: intestine
phosphorylated: enterocyte |
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What was significant about this vitamin's discovery?
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first vitamin discovered - by Eijkman in 1897
*began vitamin age |
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What carriers are involved in thiamin absorption into the enterocyte?
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ThTr 1 & ThTr 2
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What interferes with thiamin absorption?
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Ethanol
Raw fish and tannins (contain anti-thiamin factors) |
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What enzyme found in raw fish and tannins destroys thiamin?
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thiaminase
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Where is thiamin primarily absorbed?
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Jejenum
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What happens once free thiamin is absorbed into enterocyte?
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METABOLIC TRAPPING!
* free thiamin phosphorylated to TDP (thiamin diphosphate) so transporters cant take the thiamin out and back into the intestine again |
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How is thiamin transported in the blood?
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in the free form, bound to ALBUMIN
or as TMP (thiamin monophosphate) |
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What 4 vitamins are involved in energy metabolism in which pyruvate is converted to acetyl CoA?
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Thiamin
Riboflavin (becomes FAD) Niacin (becomes NAD) Pantothenic acid (makes acetyl CoA) |
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Why is it impossible to form fat from glucose?
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Because the process of converting pyruvate to acetyl CoA is IRREVERSIBLE
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In the first step of energy metabolism of pyruvate, what is removed from pyruvate?
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CO2
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What compound is left once CO2 has been removed from pyruvate, and attaches to TDP, forming what?
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hydroxyethyl, forming hydroxyethyl TDP
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After being transferred from pyruvate to TDP, what compound does TDP transfer the hydroxyethyl group to next?
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oxidized lipoamide
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What compound is generated once the hydroxylethyl group is transferred from TDP?
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Acetyl lipoamide
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How is thiamin involved in the HMP shunt?
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Transketolase uses thiamin as a cofactor
*needed for NADPH and pentoses synthesis |
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How is thiamin excreted?
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in the URINE, intact or metabolized
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What groups of people need more than the RDA?
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pregnant, lactation, alcoholics, renal pt's, PEM, and ppl with high CHO consumption (because of thiamin's involvement with glucose conversion)
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What is the deficiency syndrome associated with thiamin?
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Beri Beri
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What is dry beri beri?
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the neuritic form
*chronic def. in older adults |
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What is wet beri beri?
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cardiovascular form
*associated with EDEMA, ocular disturbances, peripheral neuropathy |
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Which form of Beri Beri is the original form?
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wet beri beri
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What is the storage form of Thiamin?
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TDP ( about 30 mg)
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What condition is frequently found among alcoholics in which thiamin is a key vitamin involved?
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Wernicke-Korsakoff syndrome
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One of the symptoms associated with wernicke-korsakoff syndrome is ataxia, what is that?
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peripheral inability to control muscle movements
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How is thiamin assessed?
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measuring erythrocyte transketolase activity in whole blood
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If the activity of transketolase is increased by > 40%, what does that indicate?
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Beri Beri
*how deficient you are depends on how much the activity increases when you add TDP |
