Term
| What vitamins are water soluble? |
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Definition
| Vit B(1-9 and 12) and Vit C |
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Term
| What are the fat soluble vitamins? |
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Definition
|
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Term
| What vitamins play a role in hematopoiesis? |
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Definition
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Term
| Folate deficiency has what common outcome? |
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Definition
|
|
Term
| Vit B12 deficiency has what common outcome? |
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Definition
|
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Term
| Tetrahydrofolate plays a role in the nucleic acid synthesis of what processes? |
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Definition
| RBC Synthesis, Embryonic Development |
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Term
| What is required for RBC and Leukocyte synthesis? |
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Definition
| Nucleotides, Amino Acids, and Iron |
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Term
| What kind of reactions require folic acid? |
|
Definition
| One-carbon transfer reactions |
|
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Term
| What is the coenzyme form of folate? |
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Definition
|
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Term
| How does FH4 participate in metabolic reactions? |
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Definition
| Accepts or donates a single carbon unit |
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Term
| What is the main circulating form of folate? |
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Definition
|
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Term
| What is the defining characteristic of 90% of dietary folate? |
|
Definition
| Contains three or more glutamates |
|
|
Term
| What removes glutamate to enhance folate absorption in the GI? |
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Definition
|
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Term
| What is the fate of monoglutamate in the liver? |
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Definition
| Conversion to polyglutamate |
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Term
| What are the sources of one carbon units transfered by FH4? |
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Definition
| Serine, Glycine, Histidine, Formaldehyde, Formate |
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Term
| What are the various forms of FH4 when carrying a one carbon unit? |
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Definition
| Formyl, Methylene, Methyl |
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Term
| What products are formed after recieving a carbon unit from FH4? |
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Definition
| dTMP, Serine, Purines, B12-CH3 |
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Term
| What form of folate is used in purine and pyrimidine synthesis? |
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Definition
| N10-Formyl-FH4 and 5,10-Methylene-FH4 |
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Term
| Why is folate deficiency induced in cancer therapy? |
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Definition
| Due to its role in DNA synthesis |
|
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Term
| What is the function of methotrexate in cancer therapy? |
|
Definition
| Acts as a competitive inhibitor of dihydrofolate reductase, a key enzyme in pyrimidine biosynthesis |
|
|
Term
| Folate is an analog for what? |
|
Definition
| Methotrexate, a cancer therapy drug |
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Term
| How is FH4 involved in pyrimidine synthesis? |
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Definition
| Transfer of a one-carbon unit in the conversion of dUMP to dTMP |
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Term
| What other diseases other than cancer is methotrexate used to treat due to being an antagonist of folate? |
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Definition
| Rheumatoid Arthritis, Psoriasis, Asthma, Alcoholic Cirrhosis, Inflammatory Bowel Disease |
|
|
Term
| What are the side effects of taking methotrexate? |
|
Definition
| Diarrhea, Anemia (due to induced folate deficiency) |
|
|
Term
| What are the best sources of nutritional folate? |
|
Definition
| Liver, fortified cereals, legumes, vegetables, (eggs, oranges are less rich source) |
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|
Term
| What commonly consumed animal has a liver with the highest concentration of dietary folate? |
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Definition
|
|
Term
| Folate deficiency first affects cells that are undergoing what process? |
|
Definition
|
|
Term
| How is hydrolyzed folate absorbed? |
|
Definition
| Active transport across intestinal wall |
|
|
Term
| How is formate in the form of supplements absorbed? |
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Definition
|
|
Term
| How does alcohol interfere with the absorption and storage of folate? |
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Definition
| Competes for transport proteins |
|
|
Term
| What is the function of anticonvulsants? |
|
Definition
| Inhibits folate absorption |
|
|
Term
| What daily intake of folate is thought to be chemo-preventive? |
|
Definition
|
|
Term
| What organ is a major storage site for folate? |
|
Definition
| Half of stored folate is found in the liver |
|
|
Term
| What are the consequences of folate deficiency? |
|
Definition
| Megaloblastic/Macrocytic Anemia |
|
|
Term
| What might cause folate deficiency? |
|
Definition
| Low intake, inadequate absorption, increased requirement (pregnancy), Vit B12 deficiency, excessive excretion |
|
|
Term
| Folate deficiency first affects what specific cells? |
|
Definition
| Early RBC synthesis in bone marrow |
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|
Term
| Folate deficiency in a developing fetus may result in what? |
|
Definition
| Neural tube defects - Spina Bifida or Anencephhaly |
|
|
Term
| Folate deficiency inhibits DNA synthesis, causing what distinct change in RBC synthesis? |
|
Definition
| RBCs remain megaloblasts, oversized and retain nuclei |
|
|
Term
| What vitamin is necessary for folate utilization in RBC development? |
|
Definition
|
|
Term
| What are common symptoms of folate deficiency? |
|
Definition
| Tongue/mouth inflammation, weakness, diarrhea, poor growth, depression, mental confusion |
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|
Term
| Vit B12 deficiency leads to what clinical condition? |
|
Definition
|
|
Term
| What mineral is contained in Vit B12 |
|
Definition
|
|
Term
| Vit B12 is synthesized exclusively by what? |
|
Definition
|
|
Term
| Vit B12 is released from proteins by actions of what? |
|
Definition
|
|
Term
| Free Vit B12 binds to what protein synthesized by the salivary glands? |
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Definition
|
|
Term
| What releases Vit B12 from the R-protine/Vit B12 complex? |
|
Definition
| Pancreatic proteases (trypsin) |
|
|
Term
| What binds to Vit B12 in the stomach? What cells secrete this protein? |
|
Definition
| Intrinsic Factors secreted by Parietal Cells |
|
|
Term
| Where does the IF/Vit B12 complex travel to? |
|
Definition
| Ileum where it binds to a receptor for absorption |
|
|
Term
| What does B12 attach to in enterocytes to enter the portal blood? |
|
Definition
|
|
Term
| How is Vit B12 delivered to tissues? |
|
Definition
| Trancobalamin II receptor from portal blood |
|
|
Term
| Vit B12 is a required coenzyme for what two conversion reactions? |
|
Definition
Methylmalonyl CoA --> Succinyl Coa by Methylmalonyl CoA Mutase
Homocystein --> Met by Methionine Synthase or Homocysteine Methyl Transferase |
|
|
Term
| Schelling Test for Vit B12 deficiency is based on what reaction? |
|
Definition
| Methylmalonyl CoA --> Succinyl CoA by Methylmalonyl CoA Mutase |
|
|
Term
| How does a lack of methionine impact cells of the nervous system? |
|
Definition
|
|
Term
| What is the methyl group donor in Met synthesis? |
|
Definition
| Methyltetrahydrofolate (MTHF) |
|
|
Term
| How is Met synthesis involved in DNA synthesis? |
|
Definition
| Frees THF to participate in DNA synthesis |
|
|
Term
| What is Pernicious Anemia? |
|
Definition
| Vit B12 deficiency, causes death within 2-5 years of diagnosis |
|
|
Term
| What causes juvenile pernicious anemia? |
|
Definition
| Defective production of Intrinsic Factor by gastric parietal cells |
|
|
Term
| List other causes of Vit B12 Deficiency other than low intrinsic factor |
|
Definition
| Bacterial overgrowth in small intestine, tapeworm, antiulcer medications, AIDS, pancreatic disease, Crohn's disease (absence of ileum/stomach) |
|
|
Term
| How long does B12 deficiency take to develop due to a vegan diet? |
|
Definition
|
|
Term
| Intrinsic Factor Failure causes Vit B12 deficiency in how many years? |
|
Definition
|
|
Term
| What are the most nutrient dense sorces of Vit B12 |
|
Definition
| Organ meats > Seafood > Beef > Eggs > Hot Dogs > Ham > Dairy |
|
|
Term
| How is Vit B12 deficiency treated? |
|
Definition
| Supplements through injection, nasal gel, or orally |
|
|
Term
| What symptoms other than those also seen in folate deficiency are clinical signs of B12 deficiency? |
|
Definition
| Nerve degeneration, sensory disturbances, dementia, loss of bowel and bladder control |
|
|
Term
| S-Adenosylmethionine (SAM) is an essential single carbon donor for the synthesis of what? |
|
Definition
| Epinepherine, Creatine, Methylated nucleotides, Phosphatidylcholine, Melatonin |
|
|
Term
| What is the methyl donor for SAM synthesis? |
|
Definition
| Methionine from homocysteine |
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|
Term
| Vit B12 deficiency results in the accumulation of what substance for what reason? |
|
Definition
| Homocysteine due to inhibited DNA synthesis (THF is trapped in methy-bound form) |
|
|
Term
| What is the fate of homocysteine? |
|
Definition
| Methylated to methionine (requires MTHF, Vit B12) or condensed with serine to form cystathionine (requires pyridoxal phosphate, Vit B6) |
|
|
Term
| High homocysteine is linked to what diseases? |
|
Definition
| Cardiovascular and Neurological diseases |
|
|
Term
| How does high homocysteine levels increase risk of cardiovascular disease? |
|
Definition
| Inhibits glutathione peroxidase, low glutathione increases oxidized LDL |
|
|
Term
| What happens to RBC as a result of Vit B12 deficiency? |
|
Definition
|
|
Term
| What is the secondary route to prevent homocysteine accumulation? |
|
Definition
| Choline used to synthesize betain in the liver can donate a methyl group to homocystein, forming methionine |
|
|
Term
| What decreases the risk of neural tube defects during embryonic development? |
|
Definition
| Folate supplements before conception and up to 1 month following conception |
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