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Biochemistry

QuestionAnswer
1. Fat soluble vitamins 2. Only water soluble vitamin stored in body. Where is it stored? 1. A, D, E, K 2. B12; stored in liver
Deficiency results in: 1. Vitamin A 2. Vitamin B1 1. night blindness 2. thiamine deficiency: Beriberi and Wernicke-Korsakoff
Describe the two variants of beriberi? 1. Dry beriberi: muscle wasting and neuropathy 2. Wet beriberi: neuropathy + cardiac failure (dilated cardiomyopathy)
1. Diarrhea, dermatitis and dementia 2. What is the vitamin deficiency? 3. Which inherited disorder has a similar presentation? 1. Pellegra 2. Vitamin B3 - niacin 3. Hartnup disease (↓ tryptophan absorption)
Which vitamin deficiency results in: 1. Wernicke-Korsakoff 2. megaloblastic anemia 3. megaloblastic anemia with neurologic symptoms 1. Vitamin B1 (thiamine) 2. Folic acid 3. Vitamin B12
Two actions of vitamin B12 1. conversion of homocysteine to methionine 2. conversion of methylmalonyl-CoA to Succinyl-CoA
Which vitamin deficiency results in: 1. Rickett's in children; osteomalacia in adults 2. Hemolytic anemia, ataxia, peripheral neuropathy 3. Easy bruising and poor wound healing 1. Vitamin D 2. Vitamin E (similar to B12) 3. Vitamin C
Vitamin K deficiency 1. Prothrombin time 2. bleeding time 3. How does vitamin C deficiency differ? 1. increased PT 2. normal bleeding time 3. normal PT, increased bleeding time
1. Mechanism of Disulfuram 2. Mechanism of Fomepizole 1. inhibits acetaldehyde dehydrogenase 2. inhibits alcohol dehydrogenase
1. Malnutrition problem resulting in skin lesions, edema and fatty liver 2. What is the fatty liver due to? 1. Kwashkior - protein malnutrition 2. ↓ apolipoprotein B100 which mediates VLDL secretion from liver
Malnutrition resulting in tissue and muscle wasting, loss of subcutaneous fat Marasmus - Protein and carbohydrate malnutrition
Cell site of: 1. fatty acid oxidation 2. fatty acid synthesis 3. glycolysis 4. TCA cycle 1. mitochondria 2. cytoplasm 3. cytoplasm 4. mitochondria
Hexokinase vs Glucokinase 1. inhibition 2. affinity to glucose 3. tissue location 4. activation Hexokinase 1. feedback inhibition by G6P 2. high affiniy 3. most cells Glucokinase 1. no inhibition 2. low affinity 3. liver 4. insulin
First step in glycolysis conversion of glucose to glucose 6 phosphate by hexokinase/glucokinase
Three causes of vitamin B3 deficieny 1. Hartnup (↓ tryptophan absorption) 2. malignant carcinoid syndrome (↑ tryptophan metabolism) 3. isoniazide (↓ vitamin B6)
Peripheral neuropathy and dermatitis from isoniazide usage is due to: B6 deficiency
1. Where is vitamin D hydroxylated? 2. What role does PTH have in vitamin D metabolism? 1. liver and kidney 2. PTH induces 1α-hydroxylase in kidney
Why does ethanol cause hypoglycemia? 1. alcohol and acetaldehyde dehydrogenase cause ↑NADH/NAD+ ratio in liver 2. ↑NADH diverts pyruvate to lactate and OAA to malate inhibits gluconeogenesis
When energy (ATP) levels in a cell are adequate, what inhibits the following: 1. glycolysis 2. pyruvate dehydrogenase 3. TCA cycle 1. ATP inhibits PFK1 and pyruvate kinase 2. acetyl CoA 3. ATP inhibits isocitrate dehydrogenase
1. Why can't fat be used to gluconeogenesis? 2. Role of biotin 1. pyruvate dehydrogenase in irreversible 2. cofactor for carboxylation enzymes (pyruvate carboxylase, acetyl coA carboxylase)
If ATP is high in the liver after a meal, PFK1 is inhbited. How do hepatocytes overcome this inhibition to continue producing acetyl CoA for storage? insulin stimulated PFK2 to produce F-2,6BP which overrides the inhibition of PFK1 and causes glycolysis to proceed
What are the rate-determining enzymes: 1. glycolysis 2. gluconeogenesis 3. TCA cycle 4. glycogen synthesis 1. PFK1 2. Fructose-1,6-bisphosphatase 3. isocitrate dehydrogenase 4. glycogen synthase
What are the rate-determining enzymes: 1. glycogenolysis 2. HMP shunt 3. De novo pyrimidine synthesis 4. De novo purine synthesis 1. glycogen phosphorylase 2. G6P dehydrogenase 3. carbamoyl phosphate synthetase II 4. glutamine PRPP amidotransferase
What are the rate-determining enzymes: 1. Urea cycle 2. fatty acid synthesis 3. fatty acid oxidation 4. ketogenesis 5. cholesterol synthesis 1. carbamoyl phosphate synthetase I 2. acetyl-CoA carboxylase 3. Carnitine acyltransferase I 4. HMG-CoA synthase 5. HMG-CoA reductase
Which enzymes does Vitamin B1 (thiamine) serve as cofactor for? 1. pyruvate dehydrogenase 2. α-ketoglutarate dehydrogenase 3. transketolase 4. branched-chain AA dehydrogenase
Which 5 cofactors are necessary for pyruvate dehydrogenase? "Tender Loving Case For Nancy" 1. Thiamine 2. Lipoic acid 3. CoA (B5, pantothenate) 4. FAD (B2, riboflavin) 5. NAD (B3, niacin)
Which enzymes are involved in pyruvate metabolism: 1. alanine → pyruvate 2. pyruvate → oxaloacetate 3. pyruvate → acetyl CoA 4. pyruvate → lactate 1. ALT 2. pyruvate carboxylase 3. pyruvate dehydrogenase 4. lactate dehydrogenase
1. What does cyanide bind in cells? 2. What does carbon monoxide bind? 3. What is the treatment for cyanide? 1. Fe3+ of ETC complex 4 2. Fe2+ of heme groups 3. nitrites convert hemoglobin to methemoglobin (Fe3+) which bind cyanide in the blood before reaching tissues
What is the Cori cyce? 1. glucose → pyruvate → lactate in skeletal muscle and RBCs 2. Lactate converted back to glucose in hepatocytes
Enzyme deficiency when Fructose-1-phosphate accumulates in hepatocytes Fructose intolerance; aldolase B deficiency
Benign syndrome in which a defective enzyme results in fructose in the blood and urine. Essential fructosuria; fructokinase deficiency
What is the overall role of glucose-6-phosphate dehydrogenase in detoxifying free radicals. 1. G6PD produces NADPH 2. NADPH reduces glutathione 3. glutathione detoxifies free radicals and peroxides
Accumulation of galactose substances results in development of cataracts, hepatosplenomegaly and mental retardation. Galactosemia; absence of galactose-1-phosphate uridyltransferase
Mild condition of galactose metabolism resulting in infantile cataracts. Galactokinase deficiency
1. Enzyme responsible for sorbitol accumulation in tissues? 2. Which tissues are most effected? 1. aldose reductase 2. schwann cells, lens, retina and kidneys
Liver or kidney dysfunction 1. ↑ BUN 2. ↓ BUN 3. Hyperammoniemia 1. kidney 2. liver 3. liver amino acid catabolism generates NH4+ which is converted to urea in the liver and excreted by the kidneys
1. Increased phenylalanine in newborn 2. What are the two possible causes cause? 1. phenylketonuria 2. ↓ phenylalanine hydroxylase or dihydrobiopterin → phenylalanine buildup and deficiency in tyrosine
1. Dark connective tissue, black urine upon standing? 2. What is the deficient enzyme? 1. alkaptonuria 2. homogentisic acid oxidase necessary to degrade tyrosine to fumarate
2 causes of homocysteinuria 1. cystathionine synthase 2. hemocysteine methyltransferase deficiency
1. Blocked degradation of branched amino acids 2. What enzyme is deficient? 1. maple syrupe urine disease 2. α-ketoacid dehydrogenase
Hereditary defect in excretion of basic amino acid results in kidney stones. cystinuria - defective transport of cysteine, ornithine, lysine, and arginine in the PCT of kidneys
1. Which enzyme mediates glycogenolysis? 2. How does insulin regulate this enzyme? 1. glycogen phosphorylase 2. insulin stimulates protein phosphatase which inactivates glycogen phosphorylase and inactivates glycogen phosphorylase kinase
Severe fasting hypoglycemia, elevated liver glycogen, hepatomegaly. Von Gierke's disease; Glucose-6-phosphatase deficiency
Glycogen storage disease resulting in cardiomegaly and systemic findings leading to early death Pompe's disease; lysosomal α-1,4-glucosidase deficiency (acid maltase)
Glycogen storage disorder with painful muscle cramps and myoglobinuria with strenuous exercise. McArdle's disease; skeletal muscle glycogen phosphorylase deficiency
Hepatosplenomegaly, glucocerebroside accumulations. Gaucher's disease; β-glucocerebrosidase
Child with progressive neurodegeneration, hepatosplenomegaly, cherry red spot on macula. Niemann-Pick disease; Sphingomyelinase deficiency
Child with progressive neurodegeneration, developmental delay and cherry red spot on macula. Tay-Sachs disease; Hexosaminidase A deficiency (Warren Tay was an ophthalmologist)
Cellular accumulation of: 1. GM2 ganglioside 2. sphingomyelin 3. Galactocerebroside 4. Glucocerebroside 1. Tay-Sachs disease; Hexosaminidase A deficiency 2. Niemann-Pick disease; Sphingomyelinase deficiency 3. Krabbe's disease; Galactocerebrosidase deficiency 4. Gaucher's disease; glucocerebrosidase deficiency
Developmental delay, gargoylism, hepatosplenomegaly. Hurler's syndrome; α-L-iduronidase deficiency
1. Delivers dietary TG's to peripheral tissues and liver. Secreted by the intestines. 2. Delivers TG's to peripheral tissues. Secreted by the liver. 1. chylomicrons 2. VLDL
Major apolipoproteins 1. binds LDL receptor 2. cofactor for lipoprotein lipase 3. mediates chylomicron secretion 4. mediates VLDL secretion 5. VLDL and chylomicron remnant reuptake by liver 1. apoB-100 2. apoC-II 3. apoB-48 4. apoB-100 5. apoE
Cause of the following familial dyslipidemias: 1. ↑ LDL (cholesterol) 2. ↑ chylomicrons (triglycerides, cholesterol) 3. ↑ VLDL (triglycerides) 1. familial hypercholesterolemia - absent LDL receptor 2. hyperchylomicronemia - lipoprotein lipase deficiency or altered apo C-II 3. hypertriglyceridemia - hepatic overproduction of VLDL
X-linked recessive lysosomal storage disease resulting in peripheral neuropathy, angiokeratomas cardiovascular/renal disease. Fabry's disease
Galactocerebrosidase accumulations resulting in peripheral neuropathy, optic atrophy and developmental delays Krabbe's disease
Where are the GLUT1, GLUT2, and GLUT4 glucose transporters located and which are insulin responsive? 1. GLUT1: most tissues (RBC's, CNS) 2. GLUT2: β-slet, liver 3. GLUT4: adipocytes, skeletal muscle (insulin responsive)
Defect in ornithine transcaramoylase leads to mental retardation, seizures and ultimately death. What is the reason? Hereditary hyperammonemia
What are the essential amino acids? PVT. TIM HALL 1. phenylalanine 2. valine 3. threonine 4. tryptophan 5. isoleucine 6. methionine 7. histidine 8. arginine 9. leucine 10.lysine
What two features distinguish B12 deficiency from folate deficiency? 1. neurological symptoms 2. elevated methylmalonic acid
1. Where are fat soluble vitamins absorbed in the body? 2. Tapeworm leading to B12 deficiency 1. ileum 2. Diphyllobothrium latum
1. Which chemical reaction is THF used for? 2. If a defective urea cycle enzyme was the cause hyperammonemia, what would you expect the BUN to be? 1. Used to donate a 1-carbon/methyl group 2. decreased
Which metabolic cycles occur in both the mitochondria and the cytoplasm? HUGs take two 1. Heme synthesis 2. Urea cycle 3. Gluconeogenesis
Which enzymes have the following effect and are stimulated by insulin: 1. glycolysis 2. liver synthesis of fatty acids 3. glycogen synthesis 1. glucokinase, PFK2, PDH 2. acetyl CoA carboxylase 3. glycogen synthase
Which enzymes of glycolysis require ATP? 1. hexokinase/glucokinase 2. PFK-1
Which enzymes of glycolysis produce ATP? 1. Phosphoglycerate kinase 2. Pyruvate kinase 3. pyruvate dehydrogenase
Why does giving glucose alone to an alcoholic lead to lactic acidosis? 1. to progress through glucolysis, pyruvate dehydrogenase requires thiamine (B1) 2. glycolysis ↑ to regenerate ATP but PDH deficiency causes shunting toward lactic acid
What are the 3 gluconeogenis substrates? 1. alanine 2. lactate 3. glycerol 3-P
1. Amino acids required during periods of growth 2. Amino acids found in histones 1. arginine and histidine 2. arginine and lysine
What causes hyperammonemia vs hyperuricemia? 1. hyperammonemia is caused by liver disease or defective urea cycle enzymes 2. huperuricemia is caused by ↑ purine turnover or gout
Albinism is a congenital deficiency of: (2 possibilities) 1. tyrosinase 2. defective tyrosine transporters
What are the branched chain amino acids? I Love Vermont maple syrupe 1. Isoleucine 2. Valine 3. Leucine
What are the two main ketone bodies? 1. acetoacetate 2. β-hydroxybutyrate
Which two deficiencies can lead to fasting hypoglycemia and low ketones? 1. Acyl-CoA dehydrogenase deficiency 2. Carnitine deficiency
What role does folate have in DNA synthesis? N5N10 methylene THF is used with thymidylate synthase to create dTMP from dUMP
Which enzyme, found only in the liver, converts G6P to glucose for entrance into the bloodstream? Glucose 6-phosphatase
Which vitamin is used to synthesize: 1. FAD 2. NAD 1. B2 (riboflavin) 2. B3 (niacin)
In skeletal muscle, how is glycogen degraded to increase glucose supply for contracting muscle? 1. calcium from the sarcoplasmic reticulum binds calmodulin and increases glycogen phosphorylase kinase 2. phosphorylase kinase activates glycogen phosphorylase leading to glycogenolysis
How long is the body reliant upon glycogen for energy between meals? 24 hours
Which cells in the body are able to metabolize fructose and galactose? hepatocytes
Which step of the TCA cycle undergoes substrate level phosphorylation? succinyl-CoA is converted to succinate to produce GTP
1. Which portion of collagen synthesis requires vitamin C? 2. Which portion of collagen synthesis requires copper? 1. hydroxylation of proline and lysine residues 2. cross linking of collagen fibrils
1. In riboflavin deficiency, with ETC component would be deficient? 2. Cause of propionic acidemia 1. succinate dehydrogenase - B2 is used to synthesize FAD, an electron carrier of the TCA cycle 2. Deficiency of propionyl CoA carboxylase
Which organs metabolize: 1. fructose 2. galactose 1. liver, kidney 2. liver, brain
1. Which vitamin deficiency ↑ vulnerability to measles 2. allosteric activator of carbamoyl phosphate synthase I 1. vitamin A 2. N-Acetylglutamate
Which neurotransmitters require tetrahydrobpterin as a cofactor all catecholamines and serotonin
What enzymes can be defective in Ehler's danlos 1. lysyl oxidase 2. pro-collagen peptidase
Which steps of collagen synthesis occur outside the fibroblast? 1. cleavage of terminal regions of procollagen to form tropocollagen then cross-linking by lysyl oxidase to make collagen fibrils
Enzymatic deficiency leading to blackening of the skin and premature atherosclerosis homocystinuria
What is NADPH from the hexose monophosphate shunt used for? 1. producing reduced glutathione 2. cholesterol and fatty acid synthesis
What is the end product of sorbitol metabolism in the lens of healthy individuals fructose
Where does the normal metabolism of fructose enter into glycolysis? glyceraldehyde 3P
Growth retardation, seizures, musty body odor phenylketonuria
Infant with vomiting, lethargy and burnt sugar smell in diaper maple syrup urine disease - branched chain amino acid dehyrogenase deficiency (required thiamine B1)
Where does β-oxidation occur: 1. medium and short chain fatty acids 2. very long chain fatty acids 1. mitochondria 2. peroxisome
Created by: amichael87