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First Aid Biochemistry 2
5.24.12
248
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05/24/2012

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Term
What are teh findings of pregnancy quad screen for patients with trisomy 18?
Definition
decreased AFP, decreased beta HCG, decreased estriol, normal inhibin A
Term
What are the findings in Patau's syndrome?
Definition
severe mental retardation, rocker bottom feet, microphthalmia, microcephaly, cleft lip/palate, holoprosencephaly, polydactyly, congenital heart disease
Term
What are the results of the pregnancy quad screen for Patau's syndrome?
Definition
normal alpha fetoprotein, normal beta hCG, normal estriol, normal inhibin A
Term
Which chromosomes are commonly involved in Robertsonian translocations?
Definition
13, 14, 15, 21, and 22
Term
What is the mutation in cri-du-chat?
Definition
microdeletion of the short arm of chromosome 5
Term
What are the findings in Cri-du-chat?
Definition
microcephaly, moderate to severe mental retardation, high pitched crying/mewing, epicanthal folds, cardiac abnormalities (VSD)
Term
What is the mutation associated with williams syndrome?
Definition
congenital microdeletion of long arm of chromosome 7 (deleted region involves the elastin gene)
Term
What are the findings of williams syndrome?
Definition
distinctive "elfin" facies, mental retardation, hypercalcemia (increased sensitivity to vitamin D), well developed verbal skills, extreme friendliness with strangers, cardiovascular problems
Term
Name some 22q11 deletion syndromes?
Definition
diGeorge Syndrome; velocardiofacial syndrome
Term
What are the findings associated with velocardiofacial syndrome?
Definition
palate, facial and cardiac defects
Term
What are teh features of 22q11 deletion syndromes?
Definition
cleft palate, abnormal facies, thymic aplasia, cardiac deficiency, hypocalcemia secondary to parathyroid aplasia
Term
Where along the gut are fat soluble vitamins absorbed?
Definition
ileum
Term
Excessive mineral oil intake can lead to...
Definition
fat soluble vitamin deficiencies
Term
Which water soluble vitamins are stored in teh liver?
Definition
B12 and folate
Term
B complex deficiencies often result in what symptoms?
Definition
dermatitis, glossitis, and diarrhea
Term
What vitamin becomes CoA?
Definition
pantothenic acid (B5)
Term
What are the functions of vitamin A in the body?
Definition
antioxidant, constituent of visual pigments (retinal); essential for normal differentiation of epithelial cells into specialized tissues (pancreatic cells, mucus secreting cells), prevents squamous metaplasia
Term
What is retinol used to treat?
Definition
measles and AML, subtype M3; topically for wrinkles and acne
Term
What are teh symptoms of vitamin A def?
Definition
night blindness, and dry skin
Term
What are the symptoms of vitamin A excess?
Definition
arthralgias, fatigue, headaches, skin changes, sore throat, alopecia
Term
What are the teratogenic effects of excess vitamin A?
Definition
cleft palate, cardiac abnormalities
Term
What is teh biologically active form of vitamin B1?
Definition
thiamine pyrophosphate (TPP)
Term
What is the function of vitamin B 1?
Definition
turns into TPP which is a cofactor for several enzymes in decarboxylation reactions: pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, transketolase, branched chain amino acid dehydrogenase
Term
What are teh symptoms of wernicke-korsakoff?
Definition
confusion, ataxia, and opthalmoplegia are the classic triad; also, confabulation, personality change, memory loss (permanent)
Term
What causes wenicke korsakoff?
Definition
def in B1 which results in damage to the medial dorsal nu of the thalamus and mamillary bodies
Term
What is the permanent symptom of wernicke korsakoff?
Definition
memory loss
Term
What are teh symptoms of dry beriberi?
Definition
polyneuritis, symmetrical muscle wasting
Term
What are the symptoms of wet beri beri?
Definition
high output cardiac failure (dilated cardiomyopathy) and edema
Term
A deficiency in thiamine causes symptoms by what mechanism?
Definition
impaired glucose breakdown --> ATP depletion; highly aerobic tissues are affected first (brain and heart) are affected first
Term
Why does alcoholism cause B1 deficiency/
Definition
both malnutrition and malabsorption contribute
Term
What is the funciton of riboflavin?
Definition
cofactor in oxidation and reduction (FADH2)
Term
What nutrient is FMN derived from?
Definition
riboflavin
Term
What are the symptoms of riboflavin deficiency?
Definition
cheilosis and corneal neovascularization
Term
What amino acid can be used to make a vitamin?
Definition
niacin can be derived from tryptophan; synthesis requires B6
Term
What can cause niacin deficiency?
Definition
hartnup disase (d/t decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and INH (decreased vitamin B6)
Term
What are the symptoms of B3 deficiency?
Definition
glossitis; severe defiency= pelagra (diarrhea, dermatitis, dementia)
Term
What is the function of B5?
Definition
essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase
Term
A deficiency in pantothenate can result in what symptoms?
Definition
dermatitis, enteritis, alopecia, and adrenal insufficiency
Term
What kinds of reactions need vitamin B6?
Definition
transamination (ALT, AST), decarboxylation, and glycogen phosphorylase
Term
Pyridoxine is necessary in the synthesis of what molecules?
Definition
cystathionine, heme, niacin, and GABA
Term
Deficiency in vitamin B6 can lead to what symptoms?
Definition
convulsions, hyperirrtability, peripheral neruopathy, sideroblastic anemia (due to impaired Hb syntehsis and Fe excess)
Term
What medications can induce a B6 deficiency?
Definition
niacin and birth control pills
Term
What is the function of cobalamin?
Definition
cofactor for homocysteine methyltransferase (transferse CH3 group as methylcobalamin to form methionine from homocysteine) and methylmalonyl-CoA mutase (turns methylmalonyl-CoA into succinyl-CoA)
Term
Where does cobalamin come from?
Definition
syntehsized by microorganisms (found in animal products)
Term
Diphyllobothrium latum causes a deficiency in what?
Definition
cobalamin
Term
What are teh neurologic symptoms of B12 deficiency?
Definition
paresthesias, subacute combined degeneration
Term
What vitamin is necessary for the breakdown of homocysteine?
Definition
you need B12 (with THF) to turn it into methionine; or B6 to turn it into cysteine
Term
Succinyl-CoA with the help of B6 can form...
Definition
hb
Term
What is the most common vitamin deficiency in the US?
Definition
folate deficiency
Term
What states predispose to folate deficiency?
Definition
alcoholism and pregnancy
Term
SAM is needed for the synthesis of..
Definition
EPI from NE, phosphocreatine, and methionine from homocysteine
Term
Regeneratio of methionine (and thus SAM) is dependent on what vitamins?
Definition
B12 and folate
Term
What chemical reactions is biotin esseential for?
Definition
pyruvate carboxylase (pyruvate to oxaloacetate), acetyl CoA carboxylase (acetyl CoA to malonyl CoA), propionyl CoA carboxylase (propionyl Co A to methylmalonyl CoA)
Term
What can cause biotin deficiency?
Definition
antibiotic use or excessive ingestion of raw eggs (avidin in egg whites binds biotin)
Term
What are the symptoms of biotin deficiency?
Definition
dermatitis, alopecia, enteritis
Term
What are the functions of vitamin C in the body?
Definition
facilitates iron absorption by keep iron in Fe2+ reduced state, necessary for hydroxylation of proline and lysine in collagen synthesis, necessary for dopamine beta hydroxylase, which converts dopamine to NE
Term
What are the symptoms of vitamin C excess?
Definition
N/V/D, fatigue, sleep problems , increased risk of iron toxicity in predisposed invdividuals
Term
What are thedifferent types of vitamin D that can be ingested?
Definition
D2= ergocalciferol (ingested from plants), D3= cholecalciferol (consumed in milk, formed in sun-exposed skin)
Term
What is the storage form of vitamin D?
Definition
25-OH D3
Term
What does vitamin D deficiency cause?
Definition
rickets in children; osteomalacia in adults, hypocalcemic tetany
Term
In what patients might you see vitamin D excess? deficiency?
Definition
excess= sarcoidosis (increased activation of vitamin D by epithelioid macrophages); def= dark skinned, breast feeding infants
Term
What is the function of vitamin E?
Definition
antioxidant (protects erythrocytes and membranes from free-radical damage)
Term
What are teh symptoms of vitamin E deficiency?
Definition
increased fragility of erythrocytes (hemolytic anemia); muscle weakness, posterior column and spinocerebeallar tract demyelination
Term
T/F Vitamin K is in breast milk.
Definition
false
Term
What is the function of zinc in the body?
Definition
essential for enzymes like carbonic anhydrase, lactate dehydrogenase, and in the formation of zinc fingers (transcription factor motif)
Term
What are the symptoms of zinc deficiency?
Definition
acrodermatitis enteropathica (rahs around eyes, mouth, nose and anus), delayed wound healing, hypogonadism, decreased adult hair (axillary facial, pubic), dysgeusia, anosmia, may predispose to alcoholic cirrhosis, impaired night vision, infertility, decreased mental function
Term
What nutrient deficiency may predispose to alcoholic cirrhosis?
Definition
zinc
Term
What vitamin deficiency may predispose to impaired night vision?
Definition
vitamin A OR zinc!
Term
What drug inhibits alcohol dehydrogenase?
Definition
fomepizole
Term
What is fomepizole used for?
Definition
antidote for methanol or ethylene glycol poisoning
Term
What is disulfiram?
Definition
inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates contributing to hangover symptoms)
Term
Why is methanol toxic?
Definition
metabolized to formadehyde which can cause retinal damage and death
Term
What enzyme is deficient in some asian people and leads to a flushing of the skin after consuming alcohol?
Definition
acetaldehyde dehydrogenase
Term
What is teh limiting factor for ethanol metabolism?
Definition
NAD+
Term
Why does excess ethanol ingestion lead to lactic acidosis?
Definition
excess NADH needs to be regenerated into NAD+ by conversion of pyruvate to lactate
Term
Why does excess ethanol ingestion lead to hypoglycemia?
Definition
increased production of NADH needs to be regenerated by conversion to NAD+ which is done by oxaloacetate to malate; excess NADH also stimulates fatty acid synthesis
Term
Where does acetyl CoA production take place?
Definition
mitochondria
Term
What biochemical pathways take place partially in teh cytoplasm and partly in the mitochondria?
Definition
heme synthesis, urea cycle, gluconeogenesis
Term
What's the difference between a kinase and a phosphorylase?
Definition
kinase uses ATP; phosphorylase adds inorganic phosphate onto substrate without using ATP
Term
What does a dehydrogenase do?
Definition
oxidizes a substrate
Term
What is the rate limiting enzyme of glycolysis?
Definition
phosphofructokinase-1
Term
What is the rate limiting enzyme of gluconeogenesis?
Definition
fructose-1,6-bisphosphatase
Term
What is the rate limiting step of the TCA cycle?
Definition
isocitrate dehydrogenase
Term
What is the rate limiting step of glycogen synthesis?
Definition
glycogen synthase
Term
What is the rate limiting step of glycogenolysis?
Definition
glycogen phosphorylase
Term
What is the rate limiting step of the HMP shunt?
Definition
glucose-6-phosphate dehydrogenase
Term
What is teh rate limiting step of de novo pyrimidine syntehsis?
Definition
carbamoyl phosphate synthetase I
Term
What is the rate limiting step of de novo purine syntehsis?
Definition
glutamine-PRPP aminotransferase
Term
What is the rate limiting step of the urea cycle?
Definition
carbamoyl pohsphate syntehtase I
Term
What is the rate limiting step of fatty acid synthesis?
Definition
acetyl-CoA carboxylase
Term
What is the rate limiting step of fatty acid oxidation?
Definition
carnitine acyltransferase I
Term
What is the rate limiting step of ketogenesis?
Definition
HMG CoA synthase
Term
What is the rate limiting step of cholesterol syntehsis?
Definition
HMG-CoA reductase
Term
How much ATP does aerobic metabolism of glucose produce?
Definition
32 via malate aspartate shuttle (in heart and liver); 30 via glycerol-3-phosphate shuttle (in muscle)
Term
Name some carrier molecules of acyl.
Definition
coenzyme A; lipoamide
Term
Name an activated carrier of aldehydes?
Definition
TPP
Term
What is NADPH used for?
Definition
anabolic processes, respiratory burst, P450, glutathione reductase
Term
Which enzyme that phosphorylates glucose is induced by insulin?
Definition
glucokinase (hexokinase is not induced by insulin)
Term
Which glucose phosphorylating agent is inhibited via feedback?
Definition
hexokinase is inhibited via negative feedback by glucose-6-phosphate; glucokinase is inhibited via fructose 6 phosphate
Term
What step of glycolysis require ATP?
Definition
hexokinase/glucokinase step and phosphofructokinase 1 step (fructose 6 phophate to fructose-1,6-bisphophate)
Term
What steps of glycolysis produce ATP?
Definition
phosphoglycerate kinase (1,3 BPG to 3-PG); pyruvate kinase (phosphoenolpyruvate to pyruvate), and pyruvate dehydrogenase (pyruvate to acetyl Co-A)
Term
What molecules regulate the action of phosphofructokinase-1?
Definition
negative= ATP and citrate; positive= AMP and fructose-2,6-BP
Term
What enzymes make/break down fructose-2,6-bisphosphate?
Definition
fructose bisphosphatase 2 is active in the fasting state; phosphofructokinase 2 is active in the fed state
Term
What is the function of alpha ketoglutarate dehydrogenase complex?
Definition
converts alpha ketoglutarate into succinyl-CoA
Term
What are the findings of arsenic poisoning?
Definition
arsenic inhibits lipoic acid; leading to vomiting, rice water stools, garlic breath
Term
How is pyruvate dehydrogenase complex activated by exercise?
Definition
it increases NAD+/NADH ratio; increases ADP, increases calcium
Term
Name the purely ketogenic amino acids?
Definition
lysine and leucine
Term
Name the amino acids that are both ketogenic and glucogenic?
Definition
tryptophan, tyrosine, phenylalanine, isoleucine
Term
What are the findings of pyruvate dehydrogenase deficiency?
Definition
backup of substrate (pyruvate and alanine) which can result in lactic acidosis; symptoms= neurologic deficits
Term
How do you treat pyruvate dehydrogenase deficiency?
Definition
intake of ketogenic nutrients; e.g. high fat content or increased lysine and leucine
Term
Anaerobic glycolysis is often performed in which cells?
Definition
RBCs, leukocytes, kidney medulla, lens, testes, and cornea
Term
What are the products from the conversion of pyruvate to acetyl CoA?
Definition
1 NADH, 1 CO2
Term
What molecules alter pyruvate dehydrogenase activity?
Definition
ATP, acetyl-CoA, NADH all have negative feedback on pyruvate dehydrogenase
Term
What are teh products of the TCA cycle?
Definition
3 NADH, 1 FADH2, 2 CO2, 1 GTP per acetyl CoA= 12 ATP per actyl CoA
Term
Name the intermediates of the TCA cycle?
Definition
acetyl coA and oxaloacetate--> citrate, isocitrate, alpha ketoglutarate, succinyl CoA, succinate, fumarate, malate, oxaloacetate
Term
What molecules alter citrate synthase?
Definition
ATP negatively affects
Term
What molecules alter actin of isocitrate dehydrogenase?
Definition
(-) ATP, NADH
(+) ADP
Term
What molecules inhibit alpha ketoglutarate dehyrogenase?
Definition
succinyl-CoA, NADH, ATP
Term
How many ATP per NADH? FADH2?
Definition
NADH= 3 ATP; FADH2= 2 ATP
Term
Which complex of the ETC gives teh electrons to O2?
Definition
complex IV
Term
Which complex of the electron transport chain makes ATP?
Definition
complex V
Term
What substances inhibit complex IV?
Definition
cyanide, N3, CO, H2S
Term
What is the effect of rotenone?
Definition
electron transport inhibitors
Term
What is teh effect of antimycin A?
Definition
electron tranport inhibitor
Term
What is the effect does oligomycin have on teh body?
Definition
ATP synthase inhibitor
Term
Name some uncoupling agents?
Definition
2,4-dinitrophenol, aspirin, thermogenin
Term
Name the irreversible enzymes of gluconeogenesis?
Definition
pyruvate carboxylase, PEP carboxykinase, fructose-1,6-bisphosphatase, glucose 6-phosphatase
Term
What is teh action of pyruvate carboxylase?
Definition
in mitochondria; converts pyruvate to oxaloacetate (requires biotin and ATP; activated by acetyl-CoA)
Term
What is the action of PEP carboxykinase?
Definition
located in the cytosol; turns oxaloacetate into phosphoenolpyruvate; requires GTP
Term
What is the action of fructose-1,6-bisphosphatase?
Definition
in cystosol; fructose 1,6 isphosphate to fructose 6 phosphate
Term
What is the action of glucose 6 phosphatase?
Definition
in ER; converts glucose-6-P into glucose
Term
Where else besides the liver are the enzymes of gluconeogenesis found?
Definition
kidney and intestinal epithelium
Term
Why can't muscle participate in gluconeogenesis?
Definition
it lacks glucose 6 phosphatase
Term
How do you get gluconeogenesis from fat?
Definition
you need odd chain fatty acids to yield propionyl CoA during metabolism which can enter the TCA cycle as succinyl-CoA and tereby undergo gluconeogenesis (even chain fatty acids cannot produce new glucose since they yield only acetyl-CoA equivilants)
Term
T/F No ATP is used or produced in teh HMP shunt (pentose pohsphate pathway).
Definition
true
Term
Besides NADPH, the HMP shunt also produces...
Definition
ribose for nucleotide synthesis and glycolytic intermediates
Term
Where is the HMP shunt particularly important?
Definition
lactating mammary glands, liver, adrenal cortex, RBCs
Term
What is transketolase?
Definition
reversible enzyme in the HMP shunt that requires B1
Term
What is teh action of superoxide dismutase?
Definition
converts superoxide into hydrogen peroxide
Term
What is the function of myeloperoxidase?
Definition
joins chloride with hydrogen peroxide to form hypochloric acid to kill bacteria
Term
What is the function of bacterial catalase?
Definition
to convert H202 (generated by NADPH oxidase and superoxide dismutase) into water and O2
Term
What kinds of drugs can precipitate a hemolytic anemia in patients with G6PD deficiency?
Definition
fava beans, sulfonamides, primaquine, anti-tuberculosis drugs
Term
What is the most common human enzyme deficiency that causes disease?
Definition
G6PD def
Term
What enzyme do humans use to breakdown hydrogen peroxide?
Definition
glutathione peroxidase/catalase
Term
What is the enzyme defective in essential fructosuria?
Definition
fructokinase
Term
What is the enzyme deficient in fructose intolerance?
Definition
aldolase B; fructose-1-phosphate accumulates causing a decrease available phosphate which results in inhibition of glycogenolysis and gluconeogenesis
Term
What are teh symptoms of fructose intolerance?
Definition
hypoglycemia, ,jaundice, cirrhosis, vomiting
Term
What are the symptoms of galactokinase deficiency?
Definition
galactitol accumulates; galacotse appears in blood and urine, and infantile cateracts; may initially present as failure to track objects or to develop a social smile
Term
What is teh defect in classic galactosemia?
Definition
absence of galactose 1 phosphate uridyltransferase; damage is caused by accumulation of toxic substances (including galactitol which accumulates in teh lens of the eye)
Term
What are the symptoms of classic galactosemia?
Definition
failure to thrive, jaundice, hepatomegaly, infantile cataracts, mental retardation
Term
How is sorbitol metabolized?
Definition
via sorbitol dehydrogenase and NAD+ into fructose
Term
What is the cofactor for aldose reductase?
Definition
NADPH
Term
Which cells have only adlose reductase and not sorbitol dehydrogenase?
Definition
schwann cells, lens, retina, and kidneys
Term
Which tissues have both aldose reductase and sorbitol dehydrogenase?
Definition
liver, ovaries, and seminal vesicles
Term
Name the essential amino acids?
Definition
leucine, lysine, isoleucine, tryptophan, phenylalanine, tyrosine, methionine, valine, arginine, and histidine
Term
Name the glucogenic amino acids?
Definition
methionine, valine, arginine, and histidine
Term
Name the basic amino acids.
Definition
arg, lys and his (arg is most basic; his has no charge at body pH)
Term
Which amino acids are essential during periods of growth?
Definition
arginine and histidine
Term
Name the intermediates of the urea cycle?
Definition
ornithine + carbamoyl phosphate (via ornithine transcarbamoylase) make citruline (with aspartate via argininosuccinate synthetase) makes argininosuccinate (argininosuccinase which yeilds fumarate and) arginine (arginase to urea and ornithine
Term
Where do the two nitrogens of urea come from?
Definition
one from ammonia, the other from aspartate
Term
What amino acid is used to transport ammonium?
Definition
alanine
Term
What are the effects of hyperammonemia?
Definition
excess NH4+ depletes alpha-ketoglutarate, leading to inhibition of TCA cycle
Term
What is the treatment for hyperammonemia?
Definition
limit protein in diet, benzoate or phenylbutyrate (both of which bind amino acid and lead to excretion) may be given to decrease ammonia levels
Term
What are the laboratory findings of ornithine transcarbamoylase deficiency?
Definition
increased orotic acid in blood and urine, decreased BUN, symptoms of hyperammonemia
Term
What are the derivatives of tryptophan?
Definition
need B6 to convert it into niacin; need BH4 to convert it into serotonin and then melatonin
Term
What cofactor is needed to convert histidine into histamine?
Definition
B6
Term
What are the amino acid derivatives of glycine?
Definition
need B6 to convert it into porphyrin and then heme
Term
What is the rate limiting step of heme synthesis?
Definition
amino levulinic synthase
Term
What are the derivatives of arginine?
Definition
creatine, urea, nitric oxide
Term
What are the amno acid derivatives of glutamate?
Definition
B6 to get GABA; or glutathione
Term
Name the enzymes and cofactors to get from phenylalanine to epinephrine.
Definition
phenylalanine hydroxylase (THB with NADPH), tyrosine hydroxylase (THB with NADPH), DOPA decarboxylase (vitamin B6), dopamine beta-hydroxylase (vitamin C), phenylethanolamine N-methyltransferase (SAM)
Term
What is the breakdown product of dopamine?
Definition
HVA
Term
What is the breakdown product of epinephrine?
Definition
metanephrine
Term
What is the breakdown product of norepinephrine?
Definition
VMA
Term
What molecule can enhance the action of phenylethanolamine N-methyl transferase?
Definition
SAM
Term
WHen should you screen for phenylketonuria?
Definition
2-3 days after birth
Term
What are the phenylketones?
Definition
phenylacetate, phenyllactate, phenylpyruvate
Term
T/F Phenylketonuria can lead to eczema.
Definition
true
Term
What are the malformations associated with maternal PKU?
Definition
microcephaly, mental retardation, growth retardation, congenital heart defects
Term
What is teh deficiency of alkaptonuria?
Definition
homogentistic acid oxidase in the degradative pathway of tyrosine to fumarate
Term
What is the inheritance of ocular albinism?
Definition
x linked recessive
Term
Describe the three forms of homocystinuria?
Definition
1) cystathione synthase deficiency 2) decreased affinity of cystathione synthase for pyridoxal phosphate 3) homocysteine methyltransferase deficiency
Term
What amino acid becomes essential in homocystinuria?
Definition
cysteine
Term
What is the treatment for cystathione synthase deficiency?
Definition
decrease methionine; increase cysteine and B12 and folate
Term
What is the treatment for decreased affinity of cystathionine synthase for pyridoxal pohsphate?
Definition
increase vitamin B6
Term
What are the findings associated with homocystinuria?
Definition
increased homocystine in urine, mental retardation, osteoporosis, tall stature, kyphosis, len subluxation (downward and inward), and atherosclerosis (stroke and MI)
Term
What reaction does cystathioinine synthase catalyze?
Definition
homocystine and serine with the help of B6 into cystathioinine
Term
Cystathionine is broken down into...
Definition
cysteine
Term
What is the defect in cystinuria?
Definition
hereditary defect of renal tubular amino acid transporter for cysteine, ornithine, lysine and arginine in the PCT of the kidneys; leads to kidney stones
Term
What is the treatment for cystinuria?
Definition
acetazolamide to alkalinize the urine
Term
What is the relationship between cystine and cysteine?
Definition
cystine is made of 3 cysteines connected by a disulfide bond
Term
What is the deficient enzyme in MSUD?
Definition
alpha ketoacid dehydrogenase
Term
What is the deficiency associated with Hartnup disease?
Definition
defective neutral amino acid transporter on renal and intestinal epithelial cells; causes tryptophan excretion in urine and decreased absorption from the gut leading to pellagra
Term
How is glycogen regulated by insulin and glucagon/epinephrine?
Definition
increased cAMP and protein kinase A pohsphorylates glycogen phosphorylase kinase to make it active; it phosphorylates glycogen pohsphorylase which then can break down glycogen
Term
What activates glycogen phophorylase kinase in muscle tissue?
Definition
calcium calmodulin in muscle can activate phosphorylase kinase so that glycogenolysis is coordinated with muscle activity
Term
How does insulin regulate glycogen metabolism?
Definition
tyrosine kinase activates protein phosphatase that can dephosphorylate both glycogen phosphorylase kinase and glycogen phosphorylase to inactivate them both
Term
What are the bonds that link glucose molecules together as glycogen?
Definition
branches have alpha (1,6) bonds; linkages have alpha (1,4) bonds
Term
List the first reaction of glycogen synthesis?
Definition
glucose-1-phosphate is turned into UDP-glucose via UDP-glucose pyrophosphorylase
Term
What is the deficient enzyme in von Gierke's disease?
Definition
glucose-6-phosphatase
Term
What is the deficient enzyme in pompe's disease?
Definition
lysosomal alpha 1,4 glucosidase (acid maltase)
Term
What is the deficient enzyme in Cori's disease?
Definition
debranching enzyme (alpha 1,6 glucosidase)
Term
What is the deficient enzyme in McArdle's disease?
Definition
skeletal muscle glycogen phosphorylase
Term
What are teh findings in von gierke's disease?
Definition
severe fasting hypoglycemia, increased glycogen in the liver, increased blood lactate and hepatomegally
Term
What are the findings of Cori's disease?
Definition
milder form of type 1 with normal blood lactate levels
Term
What is the deficient enzyme in fabry's disease and the accumulated substrate?
Definition
alpha galactosidase A; accumulated ceramide trihexoside
Term
What is the deficient enzyme and accumulated substrate of gaucher's disease?
Definition
glucocerebrosidase; glucocerebroside
Term
What are the findings in Fabry's disease?
Definition
peripheral neuropathy of hands/feet; angiokeratomas, cardiovascular/renal disease
Term
What are the findings in Gaucher's disease?
Definition
hepatosplenomegally, aseptic necrosis of the femur, bone crises, gaucher's cells (macrophages that look like crumpled tissue paper)
Term
What is the most common sphingolipidosis?
Definition
Gaucher's disease
Term
What are the findings in Niemann-Pick disease?
Definition
progressive neurodegeneration, hepatosplenomegaly, cherry red spot on macula, foam cells
Term
What is the deficient enzyme and accumulated substrate of Neimann-Pick disease?
Definition
deficient enzyme is sphingomyelinase; accumulated substrate is sphingomyelin
Term
What are the findings in Tay-Sachs disease?
Definition
progressive neurodegeneration, developmental delay, cherry red spot on macula, lysosomes with onion skin, no hepatosplenomegaly (versus Neiman Pick)
Term
What is the deficient enzyme and accumulated substrate of tay-sachs diseae?
Definition
deficient enzyme= hexosaminidase A; accumulated substrate= GM2 ganglioside
Term
What are the findings in Krabbe's disease?
Definition
peripheral neuropathy, developmental delay; optic atrophy, globoid cells
Term
What is the deficient enzyme and accumulated substrate of krabbe's disease?
Definition
beta galactocerebrosidase; galactocerebroside accumulates
Term
What are the findings in metachromatic leukodystrophy?
Definition
central and peripheral demyelination with ataxia and dementia
Term
What is the deficient enzyme and accumulated substrate of metachromatic leukodystrophy?
Definition
arylsulfatase A; cerebroside sulfate
Term
What are the findings of Hurler's syndrome?
Definition
developmental delay; gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly
Term
What is the deficient enzyme and accumulated substrate for Hurler's syndrome?
Definition
alpha-L-iduronidase; heparan and dermatan sulfate
Term
What are the findings in Hunter's syndrome?
Definition
mild Hurler's + aggressive behavior; no corneal clouding
Term
What is the deficient enzyme and accumulated substrate of Hunter's syndrome?
Definition
iduronate sulfatase; heparan sulfate and dermatan sulfate accumulate
Term
Which Sphingolipidoses have a higher incidence in ashkenazi jews?
Definition
Neimann-Pick, Tay-Sachs, and some forms of gaucher's disease
Term
What are the symptoms of carnitine deficieny?
Definition
inability to transport LCFAs into the mitochondria resulting in toxic accumulation; causes weakness, hypotonia and hypoketotic hypoglycemia
Term
What are the effects of a deficiency in Acyl-CoA dehydrogenase deficiency?
Definition
increased dicarboxylic acids; increase glucose and ketones
Term
What causes ketoacidosis in diabetes and prolonged starvation?
Definition
oxaloacetate is depleted for gluconeogenesis which stalls the TCA cycle and shunts glucose and FFA towards teh production of ketone bodies
Term
What causes ketoacidosis in alcoholism?
Definition
excess NADH shunts oxaloacetate to malate which stalls the TCA cycle and shunts glucose and FFA towards the production of ketone bodies
Term
How long does it take to use up glycogen stores?
Definition
1 day
Term
During days 1 to 3 of starvation, the liver performs gluconeogenesis by...
Definition
peripheral lactate and alanine and from adipose tissue glycerol and propionyl CoA
Term
When during starvation do ketone bodies become the main source of energy for the brain and heart?
Definition
after day 3
Term
What happens during starvation after adipose tissue is depleted?
Definition
vital protein degredation accelerates leading to organ failure and death
Term
What is the reaction catalized by HMG-CoA reductase?
Definition
HMG-CoA to mevalonate
Term
2/3 of plasma cholesterol is esterified by...
Definition
lecithin-cholesterol acyltranferase
Term
What is teh function of lipoprotein lipase?
Definition
degredation of TG circulating in chylomicrons and VLDLs
Term
What is the function of hepatic TG lipase?
Definition
degradation of TG remaining in IDL
Term
What is the function of hormone sensitive lipase?
Definition
degradation of TG stored in adipocytes
Term
What is CETP?
Definition
cholesterol ester transfer protein; mediates the transfer of cholesterol esters to other lipoprotein particles
Term
What is the function of ApoE?
Definition
mediates remnant uptake; on all lipoprotein prarticles except for LDL
Term
What is the function of Apo-A1?
Definition
activate LCAT; found on chylomicrons and HDL
Term
What is the function of Apo C II?
Definition
lipoprotein lipase cofactor; found on chylomicrons and VLDL
Term
What is the function of Apo B-48?
Definition
mediates chylomicron secretion (on chylomicrons and chylomicron remnants)
Term
What is Apo B 100?
Definition
binds LDL receptor; on VLDL, IDL, LDL
Term
What is the function of IDL?
Definition
formed in the degradation of VLDL; delivers triglycerides and cholesterol to liver, where they are degraded to LDL
Term
What is the function of LDL?
Definition
delivers hepatic cholesterol to peripheral tissues; formed by lipoprotein lipase modification of VLDL in the peripheral tissues; taken up by target cells via receptor mediated endocytosis
Term
What is the function of HDL?
Definition
mediates reverse cholesterol transport from periphery to liver; acts as a repository for apoC and apo E (which are needed for chylomicron and VLDL metabolism), secreted from both liver and intestines
Term
What is pathophysiology of type I hyperchylomicronemia?
Definition
lipoprotein lipase deficiency or altered apolpoprotein C-II; causes increased cylomicrons (increased TG and cholesterol) with pancreatitis, hepatosplenomegally or eruptive/pruritic xanthomas (no increased risk of atherosclerosis)
Term
What are the complications of type IIa familial hypercholesterolemia?
Definition
accelerated atherosclerosis, tendon (achilles) xanthomas, and corneal arcus
Term
What is the pathophysiology of type IV familial dyslipidemia?
Definition
hepatic overproduction of VLDL (increased TGs on lipid panel) causes pancreatitis
Term
What are the symptoms of abeta lipoproteinemia?
Definition
failure to thrive, steatorrhea, acanthocytosis, ataxia and night blindness that occurs within the first few months of life
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