Term
| what malabsorption syndromes can affect fat soluble vitamin absorption? |
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Definition
| CF, sprue, mineral oil intake |
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Term
| which of the water soluble vitamins do not wash out of the body? |
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Definition
| B12 and folate - stored in liver |
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Term
| what do B-complex deficiencies result in? |
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Definition
| dermatitis, glossitis and diarrhea |
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| what is the function of vit A/retinol? |
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Definition
| antioxidant, constituent of visual pigments, essential for normal differentiation of epithelial cells in to the specialized tissue (pancreatic cells/mucus-secreting cells). used to tx measles. found in liver and leafy vegetables. |
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Term
| what are signs of vit A deficiency? |
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Definition
| night blindness and dry skin |
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Term
| what are signs of vit A excess? |
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Definition
| arthralgias, fatigue, headaches, skin changes, sore throat, alopecia. teratogenic = cleft palate, cardiac abnormalities. |
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Term
| what is the function of vit B1 (thiamine)? |
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Definition
| cofactor for pyruvate dehydrogenase (glycolysis), alpha-ketoglutarate (TCA), transketolase (HMP), and branched chain AA dehydrogenase. |
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Term
| what happens w/a vit B1 deficiency? |
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Definition
| impaired glucose breakdown -> ATP depletion (glucose infusion can worsen), high aerobic tissues (brain/heart) are affected first. seen in malnutrition and alcoholism. wernicke-korsakoff: confusion, ophthalmoplegia, personality change, memory loss - damage to the medial dorsal nucleus of the thalamus and mamillary bodies. dry Ber1Ber1: polyneuritis, symmetrical muscle wasting. wet Ber1Ber1: high output cardiac failure (dilated cardiomyopathy) and edema. |
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Term
| what is the function of vit B2 (riboflavin)? deficiency? |
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Definition
| cofactor in oxidation/reduction - FAD and FMN are derived from riboFlavin. deficiency: Cheilosis (corners of mouth) and Corneal vascularization. |
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Term
| what is the function of vit B3 (niacin)? deficiency? excess? |
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Definition
| constituent of NAD+/NADP+ (NAD derived from Niacin, B3 = 3 ATP). derived from tryptophan. synthesis requires B6. deficiency: glossitis, severe = pellagra; can be due to hartnup disease (decreased tryptophan), malignant carcinoid (increased tryptophan metabolism), and INH (decreased b6). 3 D's of pellegra - Diarrhea, Dermatitis, and Dementia. excess: facial flushing (seen w/pharmacologic doses for hyperlipidemia). |
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Term
| what is the function of vit B5 (pantothenate)? deficiency? |
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Definition
| vit B5/pantothenate is an essential component of CoA and fatty acid synthase (pantothen-A is in CoA). deficiency: dermatitis, enteritis, alopecia, adrenal insufficiency. |
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Term
| what is the function of vit B6 (pyridoxine)? deficiency? |
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Definition
| vit B6/pyridoxine is converted to pyridoxal phosphate, a cofactor used in transamination (ALT and AST), decarboxylation reactions, glycogen phosphorylase, cystathionine synthesis, and heme synthesis. required fro the synthesis of niacin from tryptophan. deficiency: convulsions, hyperirritability, peripheral neuropathy (inducible by INH and oral contraceptives), and sideroblastic anemias. |
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Term
| what is the function of vit B12 (cobalamin)? deficiency? |
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Definition
| this is the cofactor for homocysteine methyltransferase. deficiency: macrocytic megaloblastic anemia, hypersegmented PMNs, neurologic symptoms (parasthesias, subacute combined degeneration) due to abnormal myelin. prolonged deficiency leads to irreversible nervous system damage. found in animal products, synthesized by microorganisms. very large reserve pool (several years) stored primarily in the liver. deficiency - usually caused by malabsorption (sprue, enteritis), lack of intrinsic factor (pernicious anemia, gastric bypass sx) or absence of terminal ileum (crohn's). schilling test is used to determine etiology. |
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Term
| what is the function of folic acid? deficiency? |
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Definition
| it is converted to tetrahydrofolate, a co-enzyme for 1-carbon transfer/methylation rxn -> important for synthesis of nitrogenous bases in DNA/RNA. small reserve stored primarily in the liver, FOLate from FOLiage. deficiency: macrocytic, megaloblastic anemia, no neurologic symptoms (as opposed to vit B12 deficiency). most common vitamin deficiency in the US - seen in alcoholism and pregnancy. deficiency can be caused by several drugs including phenytoin, sulfonamides and MTX. |
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Term
| what is S-adenosyl-methionine (SAM)? |
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Definition
| ATP + methionine -> SAM, which transfers methyl units (SAM, the methyl donor man). this is required for the conversion of NE to epinephrine. regeneration of methionine (and thus SAM) is dependent on vit B12 and folate. |
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Term
| what is the function of biotin? |
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Definition
| cofactor for carboxylation enzymes (add 1 C): pyruvate carboxylase, acetyl-CoA carboxylase, and propionyl-CoA carboxylase. deficiency: dermatitis, alopecia, enteritis (rare, caused by antibx or excessive indigestion of raw eggs). |
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Term
| what is the function of vit C/ascorbic acid? deficiency? |
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Definition
| antioxidant. facilitates iron absorption (keeps it in reduced state Fe2+), necessary for hydroxylation of proline/lysine in collagen synthesis, and necessary for dopamine beta-hydroxylase (converts DA->NE). found in fruits/vegetables. deficiency: scurvy (swollen gums, bruising, hemarthrosis, anemia, poor wound healing. weakened immune response. |
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Term
| what is the function of vit D? deficiency? excess? |
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Definition
| increased intestinal absorption of Ca++ and phosphate, increased bone resorption. D2: ergocalciferol is ingested from plants. D3: cholecalciferol is consumed in milk and formed in sun-exposed skin. 25-OH D3: storage form. 1,25-(OH)2 D3/calcitriol = active form. deficiency: rickets in children (bending bones), osteomalacia in adults (soft bones), hypocalcemic tetany, breast milk has decreased vit D (supplement in dark-skinned pts). excess: hypercalciuria, hypercalcemia, loss of appetite, stupor. seen in sarcoidosis (increased activation of vit D by epitheloid macrophages). |
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Term
| what is the function of vit E? |
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Definition
| antioxidant - protects erythrocytes/membranes (E for erythrocytes). deficiency: increased fragility of erythrocytes (hemolytic anemia), muscle weakness, posterior column and spinocerebellar tract demyelination. |
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Term
| what is the function of vit K? |
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Definition
| vit K catalyzes the gamma carboxylation of glutamic acid residues on various proteins concerned w/blood clotting. synthesized by intestinal flora. K for koagulation. warfarin = vit K antagonist. neonates are given vit K at birth to prevent hemorrhage. necessary for synthesis of clotting factors II, VII, IX, and proteins C+S. |
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Term
| what characterizes vit K deficiency? |
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Definition
| neonatal hemorrhage w/increased PT and aPTT = neonates have sterile intestines and are unable to synthesize vit K. this can also occur after prolonged use of broad-spectrum antibx. |
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Term
| what is the function of zinc? |
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Definition
| essential for the activity of 100+ enzymes. important in the formation of zinc fingers |
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Term
| what happens with zinc deficiency? |
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Definition
| delayed wound healing, hypogonadism, decreased adult hair, dysgeusia, anosmia. may predispose to alcoholic cirrhosis. |
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Term
| where does the first step of etoh metabolism occur? |
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Definition
| first: in the cytosol. etoh dehydrogenase uses NAD+ to make acealdehyde. second: in the mitochondria. acetaldehyde dehydrogenase turns acealdehyde into acetate (uses another NAD+ = the limiting reagent). fomepizole inhibits alcohol dehydrogenase and is an antidote for methanol or ethylene glycol poisoning. disulfiram inhibits acetaldehyde dehydrogenase = increased hangover symptoms. |
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Term
| how does ethanol metabolism lead to hypoglycemia and fatty acid synthesis? |
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Definition
| etoh metabolism increases NADH in the liver - which causes diversion of pyruvate to lactate and OAA to malate = inhibiting gluconeogenesis and leading to hepatic fatty change. |
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Term
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Definition
| protein malnutrition resulting in skin lesions, edema, liver malfunction (fatty change due to decreased apolipoprotein synthesis). kwashiorkor results from a protein-deficient MEAL: Malnutrition, Edema, Anemia, and Liver (fatty). |
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Term
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Definition
| energy malnutrition resulting in tissue and Muscle wasting, loss of subcutaneous fat and variable edema. |
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Term
| what parts of metabolism take place in the mitochondria? |
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Definition
| fatty acid oxidation, acetyl-CoA production, TCA cycle, and oxidative phosphorylation |
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Term
| what parts of metabolism take place in the cytoplasm? |
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Definition
| glycolysis, fatty acid synthesis, HMP shunt, protein synthesis (RER), and steroid synthesis (SER) |
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Term
| what parts of metabolism take place in both the cytoplasm and mitochondria? |
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Definition
| Heme synthesis, Urea cycle, and Gluconeogenesis. HUGs take two. |
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Term
| what does a phosphorylase do? |
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Definition
| adds and inorganic phosphate w/o ATP |
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Term
| what does a phosphatase do? |
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Definition
| removes a phosphate group |
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Term
| what does a carboxylase do? |
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Definition
| adds 1 C w/the help of biotin |
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Term
| what is the rate-determining enzyme of glycolysis? |
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Definition
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Term
| what is the rate-determining enzyme of gluconeogenesis? |
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Definition
| fructose 1 6 bisphosphate |
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Term
| what is the rate-determining enzyme of the TCA cycle? |
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Definition
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Term
| what is the rate-determining enzyme of glycogen synthesis? |
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Definition
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Term
| what is the rate-determining enzyme of glycogenolysis? |
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Definition
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Term
| what is the rate-determining enzyme of the HMP shunt? |
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Definition
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Term
| what is the rate-determining enzyme of de novo pyrimidine synthesis? |
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Definition
| carbamoyl phosphate synthetase II |
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Term
| what is the rate-determining enzyme of de novo purine synthesis |
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Definition
| glutamine PRPP amidotransferase |
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Term
| what is the rate-determining enzyme of the urea cycle? |
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Definition
| carbamoyl phosphate synthetase I |
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Term
| what is the rate-determining enzyme of fatty acid synthesis? |
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Definition
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Term
| what is the rate-determining enzyme of fatty acid oxidation? |
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Definition
| carnitine acyltransferase I |
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Term
| what is the rate-determining enzyme of ketogenesis? |
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Definition
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Term
| what is the rate-determining enzyme of cholesterol synthesis? |
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Definition
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