First Aid Biochemistry 1
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| Fat soluble vitamins | A, D, E, and K
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| Only water soluble vitamin stored in the body | B12; stored in the liver
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| Vitamin A deficiency results in? | Night blindness
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| Vitamin B1 deficiency results in? | thiamine deficiency, Beriberi and Wernicke-Korsakoff syndrome
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| Describe the two variants of beriberi? | Dry beriberi marked by muscle wasting and polyneuritis; Wet beriberi marked by cardiac failure (dilated cardiomyopathy)
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| What is Wernicke-Korsakoff syndrome? | Thiamine deficiency often as a result of alcoholic malnutrition; marked by vision changes, ataxia, and impaired memory
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| Vitamin B2 deficiency results in? | Riboflavin; Angular stomatitis
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| Vitamin B3 deficiency results in? | Niacin; Pellagra (3D's: dementia, diarrhea, dermatitis)
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| Vitamin B12 deficiency results in? | Megaloblastic anemia with neurologic changes
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| What are the two actions of B12? | Conversion of homocysteine to methionine and conversion of methylmalonyl-CoA to Succinyl-CoA; deficiency results in methylmalonic acid accumulation (Homocysteine will accumulate if B6 is deficient as well)
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| Folic acid deficiency results in? | Megaloblastic anemia w/out neurologic changes
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| Biotin deficiency is commonly caused by? | Avidin in egg whites; consumption of raw eggs
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| Vitamin C deficiency results in? | Scurvy; swollen gums, bruising, anemia, poor wound healing
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| Vitamin D deficiency results in? | Ricketts in kids; osteomalacia in adults
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| Vitamin E deficiency results in? | Hemolysis (antioxidant that protects erythrocytes) and neurodysfunction
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| Vitamin K deficiency results in? | Bleeding disorders; increased PT and PTT with normal bleeding time (normal platelets)
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| Why does ethanol cause hypoglycemia? | Consumption of NAD by alcohol dehydrogenase results in shunting of pyruvate and OAA to lactate and malate respectively, inhibiting gluconeogenesis
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| What is the mechanism of action of Disulfuram and what is it used for? | Inhibits acetaldehyde dehydrogenase leading to acetaldehyde accumulation, used in the treatment of chronic alcoholics
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| Protein malnutrition resulting in skin lesions, edema, and liver malfunction (fatty change) | Kwashkior
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| Energy malnutrition resulting in tissue and muscle wasting, loss of fat, and variable edema | Marasmus
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| Mutation in DNA repair resulting in predisposition for melanoma and other cancers. | Nucleotide excision repair; mutated in xeroderma pigmentosa
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| Mutation in DNA repair resulting in hereditary nonpolyposis colon cancer? | Mismatch repair
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| Direction of DNA and RNA synthesis | 5' to 3'
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| mRNA initiation and stop codons? | Start: AUG; Stop: UGA, UAA, UAG
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| What are the 3 steps of RNA processing? | 1. Capping 5' end w/ 7-methyl-G; 2. Polyadenylation of 3' end; 3. splicing out of introns
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| I-cell disease is a result of what dysfunction? | Failure of addition of mannose-6-phosphate to lysosome proteins, enzymes secreted outside of cell instead of targeted for destruction.
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| What are the symptoms of I-cell disease | Coarse facial features, clouded corneas, and restricted joint movements
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| Syndrome of immotile cilia resulting in infertility, bronchiectasis, and recurrent sinusitis? | Kartagener's syndrome
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| Symptoms of this disorder include skeletal abnormalities (arachnodactyly), astigmatism, and various cardiovascular problems. | Marfan's syndrome
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| Symptoms of this disorder include hyperextensible skin, easy bruising, and hypermobile joints. | Ehler-Danlos syndrome
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| Symptoms of this disorder include multiple fractures, blue sclera, hearing loss, and dental imperfections. | Osteogenesis imperfecta (hearing loss is due to abnormal middle ear bones); may be confused with child abuse
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| Site of fatty acid oxidation and Krebs cycle | mitochondria
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| Site of glycolysis, fatty acid synth, and HMP shunt | cytoplasm
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| Differences between hexokinase and glucokinase? | Hexokinase has feedback inhibition by G6P, is high affinity, low capacity, and ubiquitously expressed. Glucokinase has no inhibition, low affinity, high capacity, and only found in the liver.
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| What is the first step in glycolysis and what inhibits this step? | conversion of glucose to glucose 6 phosphate by hexokinase/glucokinase; inhibited by glucose 6 phosphate if hexokinase
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| What is the rate limiting step in glycolysis and what inhibits and activates this step? | Conversion of F-6-phosphate to F-1,6-bisphosphate by PFK1; it is inhibited by ATP and citrate, activated by F-2,6-BP (most potent)
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| What inhibits conversion of pyruvate to acetyl-CoA? | Inhibited by ATP, NADH, and acetyl-CoA
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| Describe the enzyme that regulates F-2,6-BP? | Bifunctional enzyme, FBPase 2 which is active in the fasting state and serves to generate F-2,6-BP to increase glycolysis, and PFK-2 which is active in the fed state and serves to decrease F-2,6-BP
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| Why does pyruvate kinase deficiency result in hemolytic anemia? | Because RBC's have no mitochondria and depend solely on glycolysis for energy
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| What are the 5 cofactors necessary for pyruvate dehydrogenase? | TPP (B1;thiamine), FAD (B2; riboflavin), NAD (B3; niacin), CoA (B5; pantothenate), and lipoic acid; These are also necessary for alpha-ketoglutarate DH
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| Arsenic inhibits what enzymes? | pyruvate DH and alpha-ketoglutarate DH; arsenic inhibits lipoic acid, symptoms of poisening include vomiting, rice water stools, and garlic breath
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| Necessary cofactor for gluconeogenesis conversion of pyruvate to oxaloacetate? | Biotin, ATP
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| What is the Cori cycle? | Conversion of glucose to pyruvate to lactate in skeletal muscle and RBC's by lactate dehydrogenase, and conversion of lactate back to glucose in hepatocytes also by lactate DH.
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| In the Cori cycle why is there a net negative of 4 ATP? | Yields 2 ATP to convert glucose to lactate but requires 6 ATP to convert lactate back to glucose.
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| NADPH is required for what processes? | Fatty acid and steroid synthesis, glutathione reduction in RBC's, and cytochrome-P450
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| In this syndrome, a decrease in available phosphate results in inhibition of both glycogenolysis and gluconeogenesis. | Fructose intolerance; aldolase B deficiency
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| In this benign syndrome, a defective enzyme results in fructose in the blood and urine. | Essential fructosuria
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| Accumulation of toxic galactose substances results in the development of cataracts, hepatosplenomegaly, and mental retardation. | Galactosemia; absence of galactose-1-phosphate uridyltransferase
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| Loss of this brush border enzyme leads to the development of bloating, cramps, and osmotic diarrhea. | Lactase deficiency
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| What is the cause of phenylketonuria? | Decreased phenylalanine hydroxylase or THB cofactor necessary for tyrosine synthesis leads to phenylalanine buildup and deficient tyrosine
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| What is the deficient enzyme in alkaptonuria? | Deficiency of homogenistic acid oxidase necessary to degrade tyrosine
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| What are the 3 causes of homocysteinuria? | cystathionine synthase deficiency, decreased affinity of cystathionine synthase for B6, and methionine synthase deficiency
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| This inherited defect of renal tubular amino acid transporters results in kidney stones. | Cystinuria
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| Deficient alpha-ketoacid DH results in blocked degradation of branched amino acids in this disease. | Maple syrup urine disease
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