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28 Cards in this Set
- Front
- Back
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Gluconeogenesis, irreversible enzymes
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Pyruvate carboxylase
PEP carboxykinase Fructose-1,6-bisphosphatase Glucose-6-phosphatase |
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Sites of the HMP shunt
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lactating mamary glands, liver, adrenal cortex (sites of fatty acid or steroid synthesis), RBCs
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HMP Shunt: Oxidative (irreversible reaction)
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Key enzyme: Glucose-6-phosphate dehydrogenase (rate limiting step)
Products: NADPH (for fatty acid and steroid sythesis, glutathione reduction, and cytochrome P-450) |
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HMP Shunt: Nonoxidative (reversible raction)
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Key Enzyme: transketolases (require thiamine)
Products: Ribose-5-phosphate (for nucleotide synthesis); G3P, F6P (glycolytic intermediates) |
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Respiratory Burst enzymes
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NADPH oxidase
Superoxide dismutase Myeloperoxidase Catalase/glutathione peroxidase Glutathione reductase Glucose-6-phosphate dehydrogenase (G6PD) |
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G6PD deficiency
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X-linked recessive, most common human enzyme deficiency
more prevalent among blacks increased malarial resistance Heinz bodies: Hb precipitated in RBCs Bite cells: result from phaogcytic removal of Heinz bodies by macrophages |
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Essential Glucogenic Amino Acids
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Met, Val, Arg, His
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Essential Glucogenic/ketogenic Amino Acids
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Ile, Phe, Thr, Trp
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Essential Ketogenic Amino Acids
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Leu, Lys
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X-linked Recessive Disorders
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Bruton's Agammaglobulinemia
Wiskott-Aldrich Fragile X G6PD deficiency Ocular albinism Lesch-Nyhan Duchenne and Becker's MD Fabry's and Hunter's Dzs Ornithine transcarbamoylase deficiency (OTC) |
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Ornithine transcarbamoylase (OTC) deficiency
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most common urea cycle disorder
body can't eliminate ammonia excess carbamoyl phosphate converted to orotic acid orotic acid in blood/urin, dec BUN, sxs of hyperammonemia |
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Homocystinuria
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3 forms: cystathionine synthase deficiency (tx - dec met, inc cys, inc B12 and folate); dec affinity of cystathionine synthase for pyridoxal phosphate (tx - increase vitamin B6 in diet); homocysteine methyltransferase deficiency
Findings: mental retardation, osteoporosis, tall stature, kyphosis, lens subluxation (downward and inward), and atherosclerosis |
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Von Gierke's disease (type I glycogen storage disease)
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Findings: severe fasting hypoglycemia, INCreased glycogen in liver, increased blood lactate, hepatomegaly
Deficient enzyme: glucose-6-phosphatase |
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Pompe's disease (type II glycogen storage disease)
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Findings: cardiomegaly and systemic findings leading to early death
Deficient enzyme: lysosomal a-1,4-glucosidase (acid maltase) |
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Cori's disease (type III glycogen storage disease)
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Findings: milder form of type I with normal blood lactate levels
Deficient enzyme: debranching enzyme (a-1,6-glucosidase) |
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McArdle's disease (type IV glycogen storage disease)
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Findings: increased glycogen in muscle, but cannot break it down, eading to painful muscle cramps, myoglobinuria with strenuous exercise
Deficient enzyme: skeletal muscle glycogen phosphorylase |
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Fabry's disease (sphingolipidosis)
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Findings: peripheral neuropathy of hands/feet, angiokeratomas, cardiovascular/renal disease
Deficient enzyme: a-galactosidase A Accumulated substrate: ceramide trihexoside AR |
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Gaucher's disease (sphingolipidosis)
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Findings: hepatosplenomegaly, aseptic necrosis of femur, bone crises, Gaucher's cells (macrophages tha tlok like crumpled tissue paper)
Deficient enzyme: B-glucocerebrosidase Accumulated substrate: glucocerebroside AR |
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Niemann-Pick disease (sphingolipidosis)
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Findings: progressive neurodegeneration, hepatosplenomegaly, cherr-red spot on macula, foam cells
Deficient enzyme: sphingomyelinase Accumulated substrate: sphingomyelin AR |
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Tay-Sachs disease (sphingolipidosis)
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Findings: progressive neurodegeneration, developmental delay, cherry-red spot on macula, lysosomes with onion skin
Deficient enzyme: Hexosaminidase A Accumulated substrate: GM2 ganglioside |
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Krabbe's disease (sphingolipidosis)
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Findings: peripheral neuropathy, developmental delay, optic atrophy, globoid cells
Deficient enzyme: glactocerebrosidase Accumulated substrate: galactocerebroside AR |
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Metachromatic leukodystrophy (sphingolipidosis)
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Findings: central and peripheral demyelination with ataxia, dementia
Deficient enzyme: arylsulfatase A Accumulated substrate: cerebroside sulfate AR |
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Hurler's syndrome (mucopolysaccharidosis)
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Findings: developmental delay, gargolism, airway obstruction, corneal clouding, hepatosplenomegaly
Deficient enzyme: a-L-iduronidase Accumulated substrate: heparan sulfate, dermatan sulfate AR |
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Hunter's syndrome (mucopolysaccharidosis)
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Findings: mild Hurler's + aggressive behavior, no corneal clouding
Deficient enzyme: iduronate sulfatase Accumulated substrate: heparan sulfate, dermatan sulfate XR |
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Fasting and Starvation (1-3 days); Blood glucose level maintained by:
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1) Hepatic clygogenolysis and glucose release
2) Adipose release of FFA 3) Muscle and liver shifting fuel use from glucose to FFA 4) Hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and propionyl-CoA from odd-chain FFA metabolism |
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Fasting and Starvation (after day 3)
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Muscle protein loss is maintained by hepatic formation of ketone bodies, supplying the brain and heart
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Fasting and Starvation (after several weeks)
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Ketone bodies become main source of energy for brain, so less muscle protein is degraded than during days 1-3. Survival time is determined by amount of fat stores. After this is depleted, vital protein degradation accelerates, leading to organ failure and death
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Major apolipoproteins
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A-I: activates LCAT
B-100: binds to LDL receptor, mediates VLDL secretion C-II: cofactor for lipoprotein lipase B-48: mediates chylomicron secretion E: mediates extra (remnant) uptake |
