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Questions and Answers
When water-soluble vitamins are consumed in excess of body needs, generally the excess is ____.
When water-soluble vitamins are consumed in excess of body needs, generally the excess is ____.
A major function of B vitamins is to serve as ____.
A major function of B vitamins is to serve as ____.
Most animals synthesize their own ascorbic acid from ____.
Most animals synthesize their own ascorbic acid from ____.
When ascorbic acid becomes dehydroascorbic acid, it has ____.
When ascorbic acid becomes dehydroascorbic acid, it has ____.
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Vitamin C acts as a cofactor by maintaining iron in a reduced state in ____.
Vitamin C acts as a cofactor by maintaining iron in a reduced state in ____.
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The organ that is most commonly used as a storage site for B vitamins is the ____.
The organ that is most commonly used as a storage site for B vitamins is the ____.
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Which water-soluble vitamin contributes to 'intracellular cement' in the formation of scar tissue and wound healing?
Which water-soluble vitamin contributes to 'intracellular cement' in the formation of scar tissue and wound healing?
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The B vitamin that is involved in hematopoiesis (production of blood cells) is ____.
The B vitamin that is involved in hematopoiesis (production of blood cells) is ____.
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Beriberi is a deficiency syndrome associated with ____.
Beriberi is a deficiency syndrome associated with ____.
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Without enough vitamin C, collagen would ____.
Without enough vitamin C, collagen would ____.
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A primary function of vitamin C is to act as an ____.
A primary function of vitamin C is to act as an ____.
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Vitamin C's actual participation in biochemical reactions usually involves its antioxidant ability. Choose the description of this activity.
Vitamin C's actual participation in biochemical reactions usually involves its antioxidant ability. Choose the description of this activity.
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The necessity of ascorbic acid for its role in ____ is believed to be the reason that people with scurvy have no energy and are very tired.
The necessity of ascorbic acid for its role in ____ is believed to be the reason that people with scurvy have no energy and are very tired.
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The RDA for vitamin C for adult men is ____ and the UL is ____.
The RDA for vitamin C for adult men is ____ and the UL is ____.
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In what way are water-soluble vitamins absorbed?
In what way are water-soluble vitamins absorbed?
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A major role for thiamin is ____.
A major role for thiamin is ____.
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Thiamin is important to fatty acid synthesis due to its requirement as a coenzyme for the pentose phosphate pathway enzyme ____.
Thiamin is important to fatty acid synthesis due to its requirement as a coenzyme for the pentose phosphate pathway enzyme ____.
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A consequence of thiamin deficiency is ____.
A consequence of thiamin deficiency is ____.
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Erythrocyte transketolase activity is an assay to assess the status of ____.
Erythrocyte transketolase activity is an assay to assess the status of ____.
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Riboflavin is found most often in ____.
Riboflavin is found most often in ____.
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FMN and FAD act as prosthetic groups for enzymes called ____.
FMN and FAD act as prosthetic groups for enzymes called ____.
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Cheilosis is a symptom of a dietary deficiency of which vitamin?
Cheilosis is a symptom of a dietary deficiency of which vitamin?
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When the diet is adequate in protein, the body can synthesize niacin from which amino acid?
When the diet is adequate in protein, the body can synthesize niacin from which amino acid?
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The best sources of niacin are ____.
The best sources of niacin are ____.
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Which classical vitamin deficiency is known for the four Ds: dermatitis, dementia, diarrhea, and death?
Which classical vitamin deficiency is known for the four Ds: dermatitis, dementia, diarrhea, and death?
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Which of the water-soluble vitamins is found widely distributed in all plant and animal foods, which makes a deficiency unlikely?
Which of the water-soluble vitamins is found widely distributed in all plant and animal foods, which makes a deficiency unlikely?
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Synthesis of coenzyme A starts with the phosphorylation of which vitamin?
Synthesis of coenzyme A starts with the phosphorylation of which vitamin?
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Hair loss associated with eating raw eggs may be reversed by treatment with ____.
Hair loss associated with eating raw eggs may be reversed by treatment with ____.
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Decarboxylation of pyruvate is achieved by the interaction of pantothenic acid with thiamin, riboflavin, and ____.
Decarboxylation of pyruvate is achieved by the interaction of pantothenic acid with thiamin, riboflavin, and ____.
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A deficiency of which vitamin is associated with these symptoms: hallucinations, lethargy, skin rash, alopecia, and muscle pain?
A deficiency of which vitamin is associated with these symptoms: hallucinations, lethargy, skin rash, alopecia, and muscle pain?
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Folate in foods can only be absorbed in the monoglutamate form; therefore, digestive enzymes called ____ are important for folate nutriture.
Folate in foods can only be absorbed in the monoglutamate form; therefore, digestive enzymes called ____ are important for folate nutriture.
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Consumption of raw eggs causes a biotin deficiency due to the binding of ____ to the biotin, thus preventing its absorption.
Consumption of raw eggs causes a biotin deficiency due to the binding of ____ to the biotin, thus preventing its absorption.
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Folate's discovery resulted from the search to cure ____.
Folate's discovery resulted from the search to cure ____.
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Which of the following reflects long-term folate status?
Which of the following reflects long-term folate status?
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The degradation of ____ provides the majority of one-carbon groups for pyrimidine synthesis. In this process, ____ is formed.
The degradation of ____ provides the majority of one-carbon groups for pyrimidine synthesis. In this process, ____ is formed.
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Methylation of DNA influences gene expression. Which vitamin is important in this process?
Methylation of DNA influences gene expression. Which vitamin is important in this process?
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Folate and ____ participate in the regeneration of methionine from homocysteine.
Folate and ____ participate in the regeneration of methionine from homocysteine.
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5-methyl THF requires the action of which vitamin in order to form THF?
5-methyl THF requires the action of which vitamin in order to form THF?
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Burning foot syndrome may be caused by a deficiency of ____.
Burning foot syndrome may be caused by a deficiency of ____.
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Methionine is used to synthesize S-adenosylmethionine (SAM). This is important so that ____.
Methionine is used to synthesize S-adenosylmethionine (SAM). This is important so that ____.
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Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of ____.
Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of ____.
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Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme ____.
Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme ____.
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The last vitamin to be discovered was ____.
The last vitamin to be discovered was ____.
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A cobalt deficiency may lead to ____.
A cobalt deficiency may lead to ____.
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Intrinsic factor is required for the majority of absorption of which vitamin?
Intrinsic factor is required for the majority of absorption of which vitamin?
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Vitamin B12 is absorbed in the ____.
Vitamin B12 is absorbed in the ____.
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Pyridoxine is found almost exclusively in ____.
Pyridoxine is found almost exclusively in ____.
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Free pyridoxine is yielded by the action of ____.
Free pyridoxine is yielded by the action of ____.
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Large amounts of folic acid can mask a vitamin B12 deficiency and prevent ____ from resulting. Over time, the symptoms unique to a vitamin B12 deficiency will occur, and these are related to the ____.
Large amounts of folic acid can mask a vitamin B12 deficiency and prevent ____ from resulting. Over time, the symptoms unique to a vitamin B12 deficiency will occur, and these are related to the ____.
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Which vitamin is most involved in amino acid metabolism?
Which vitamin is most involved in amino acid metabolism?
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Pellagra symptoms may appear during B6 deficiency because this vitamin is required in the process of obtaining niacin from tryptophan.
Pellagra symptoms may appear during B6 deficiency because this vitamin is required in the process of obtaining niacin from tryptophan.
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Water-soluble vitamins are not stored, but readily excreted-the one exception is that we can store folate in the liver.
Water-soluble vitamins are not stored, but readily excreted-the one exception is that we can store folate in the liver.
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Pernicious anemia can be due to folate or B12 deficiency.
Pernicious anemia can be due to folate or B12 deficiency.
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Fish are a major source of thiamin.
Fish are a major source of thiamin.
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The primary role of vitamin C is as a reducing agent, particularly for the mineral component of a number of enzymes that becomes oxidized following catalysis of a reaction.
The primary role of vitamin C is as a reducing agent, particularly for the mineral component of a number of enzymes that becomes oxidized following catalysis of a reaction.
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High circulating levels of homocysteine (i.e., hyperhomocysteinemia) have been implicated in a number of pathologies including cardiovascular disease.
High circulating levels of homocysteine (i.e., hyperhomocysteinemia) have been implicated in a number of pathologies including cardiovascular disease.
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Biotin appears to be a very safe vitamin supplement as there has been no toxicity reported from oral biotin ingestion nor is there a Tolerable Upper Intake Level established.
Biotin appears to be a very safe vitamin supplement as there has been no toxicity reported from oral biotin ingestion nor is there a Tolerable Upper Intake Level established.
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Increases in plasma holotranscobalamin TCII concentrations provide an indication of vitamin B12 absorption.
Increases in plasma holotranscobalamin TCII concentrations provide an indication of vitamin B12 absorption.
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Impaired folding and secretion of proteins have been observed with thiamin deficiency.
Impaired folding and secretion of proteins have been observed with thiamin deficiency.
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Abnormally high urinary excretion of xanthurenic acid may be an indication of niacin deficiency.
Abnormally high urinary excretion of xanthurenic acid may be an indication of niacin deficiency.
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An example of a cleavage reaction requiring PLP is the degradation of thiamin into its pyrimidine and thiazole moieties.
An example of a cleavage reaction requiring PLP is the degradation of thiamin into its pyrimidine and thiazole moieties.
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Initial research on vitamin B6 was aimed at correcting dermatitis in rats.
Initial research on vitamin B6 was aimed at correcting dermatitis in rats.
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Vitamin C's antioxidant abilities may inhibit high-density lipoprotein (HDL) oxidation, which may diminish plaque formation associated with heart disease.
Vitamin C's antioxidant abilities may inhibit high-density lipoprotein (HDL) oxidation, which may diminish plaque formation associated with heart disease.
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Most thiamin in the American diet comes from products that have been enriched.
Most thiamin in the American diet comes from products that have been enriched.
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Large doses of nicotinic acid are used to treat certain types of hyperlipidemias.
Large doses of nicotinic acid are used to treat certain types of hyperlipidemias.
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Nutrients can be used to compensate for some gaps in our DNA. For example:
Nutrients can be used to compensate for some gaps in our DNA. For example:
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How do we know that folate fortification has improved the biochemical folate status of Americans?
How do we know that folate fortification has improved the biochemical folate status of Americans?
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What is the criterion for a genetic difference to be called a 'polymorphism'?
What is the criterion for a genetic difference to be called a 'polymorphism'?
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Folic acid fortification has ____.
Folic acid fortification has ____.
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Study Notes
Water-Soluble Vitamins Overview
- Water-soluble vitamins are quickly absorbed into the portal blood system and excess is primarily excreted in urine.
- B vitamins often function as parts of coenzymes, necessary for various metabolic processes.
- The liver serves as the main storage location for water-soluble vitamins, excluding ascorbic acid (Vitamin C).
Vitamin C (Ascorbic Acid)
- Vitamin C is synthesized in most animals from glucose.
- Conversion of ascorbic acid to dehydroascorbic acid involves the loss of two electrons.
- Key functionalities include acting as a cofactor in collagen synthesis and functioning as an antioxidant by donating electrons to reduce mineral cofactors.
- Adequate intake is crucial for energy production and for preventing underhydroxylation of collagen.
- Recommended daily allowance (RDA) for adult men is 90 mg, with a tolerable upper intake level (UL) of 2,000 mg.
B Vitamins Functionality
- Thiamin (Vitamin B1) is crucial for energy production and fatty acid synthesis, utilizing the enzyme transketolase.
- Vitamin B12 is involved in hematopoiesis and requires intrinsic factor for absorption, primarily occurring in the ileum.
- Niacin (Vitamin B3) is derived from tryptophan and is essential in preventing the four D's: dermatitis, dementia, diarrhea, and death in deficiency.
- Biotin (Vitamin B7) deficiency can occur due to raw egg consumption, caused by avidin binding.
- Folate (Vitamin B9) is critical for DNA synthesis, influencing cell division and requiring digestive enzymes for absorption.
Deficiency Syndromes
- Deficiency of Vitamin B1 leads to beriberi.
- Symptoms of biotin deficiency include hallucinations, skin rash, and hair loss; treatable with biotin supplementation.
- Vitamin B12 deficiency causes megaloblastic macrocytic anemia, alongside neurologic symptoms.
- Pellagra is associated with niacin deficiency, characterized by the four D's.
Folate and Genetic Factors
- Folate plays a vital role in the regeneration of methionine from homocysteine.
- It is essential for the synthesis of purines and pyrimidines, which are crucial for cell division, particularly during growth or malignancy.
- Genetic polymorphisms affecting folate metabolism can result in elevated plasma homocysteine levels.
Research and Recommendations
- Dietary fortification of folate has significantly reduced neural tube defects (NTDs) in the population.
- Long-term folate status is best reflected through red blood cell folate levels.
- Most thiamin in the U.S. diet comes from enriched products, indicating a reliance on processed foods for this nutrient.
- Ongoing research continues to establish the relationship between nutrient supplementation and the prevention of deficiencies or related disease outcomes.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on water-soluble vitamins with this quiz based on Chapter 9. You'll explore key functions, storage, and processing of B vitamins and others. Review important concepts to ensure a thorough understanding of dietary nutrients essential for health.
