Flashcards in Biochemistry Deck (293)
aggressive behavior + mild symptoms of Hurler's syndrome (dev'l delay, gargoylism, airway obstruction, hepatosplenomegaly); heparan sulfate and dermatan sulfate accumulation
Hunter's syndrome (XR)
Hypoketotic hypoglycemia (+ weakness and hypotonia)
Carnitine deficiency: can't transport LCFAs into mitochondria, so get toxic accumulation in cytoplasm
how many kcal from 1 g protein, carb, fat?
1 g protein --> 4 kcal
1 g carb --> 4 kcal
1 g fat --> 9 kcal
LCAT = lecithin-cholesterol acyltransferase: what does it do?
takes cholesterol and puts it into HDL particles (catalyzes esterification of cholesterol)
CETP = cholesterol ester transfer protein: what does it do?
allows HDL to deposit cholesterol into LDL, etc.. (mediates transfer of cholesterol esters to other lipoprotein particles)
mediates VLDL and chylomicron remanant uptake by liver cells
activates LCAT (for cholesterol esterification)
lipoprotein lipase cofactor (LPL --> degrades TG circulating in chylomicrons and VLDLs)
mediates chylomicron secretion by the intestine and chylomicron assembly
binds LDL receptor (LDL particle uptake by extrahepatic cells)
familial dyslipidemia with increased chylomicrons, increased blood TG and cholesterol; pancreatitis, xanthomas...
type 1: hyper-chylomicronemia
-no increase risk for atherosclerosis
familial dyslipidemia with increased LDL; atherosclerosis, Achilles xanthomas, corneal arcus; elevated blood cholesterol
type IIa - familial hypercholesterolemia
-MI by age 20 if homozygous
familial dyslipidemia with increased VLDL; increased blood TGS; pancreatitis
type IV - hypertriglyceridemia
-have hepatic overproduction of VLDL
deficiencies in apo-B100 and apo-B48; FTT, steatorrhea, acanthocytosis, ataxia, night blindness
abetalipoproteinemia --> can't synthesize lipoproteins b/c no apob100 and apob48
-accumulation within enterocytes because can't export absorbed lipid as chylomicrons
facial lesions (adenoma sebaceum), hypopigmented ash-leaf spots, coritcal and retinal hamartomas, seizures, MR, renal cysts, renal angiomyolipomas, cardiac rhabdomyomas, increased incidence of astrocytomas
Tuberous Sclerosis (variable presentations)
3 mitochondrial disorders:
-Leber hereditary optic neuropathy
1) Leber Hereditary optic neuropathy --> bilateral vision loss
2) Myoclonic epilepsy with ragged red fibers --> myoclonus, seizures, myopathy assoc with exercise; irregularly shaped muscle fibers on skeletal muscle biopsy
3) MELA = mitochondrial encephalomyopathy with lactic acidosis and stroke like episodes--> seizures, stroke-like episodes with neuro-deficit, muscle weakness, increased serum lactate post-exercise and at rest
Hypoglycemia after prolonged fasting, with inappropriately low levels of ketone bodies: What enzyme is deficient?
Impaired Beta-oxidateion/Degradation of Fatty Acids; Acyl-CoA dehydrogenase deficiency
antibodies against collagen type 4?
=anti-glomerular basement membrane antibodies --> Goodpasture's syndrome! (hemoptysis + oliguria)...
recurrent nosebleeds, and pink spider-like lesions on oral and nasal mucosa, face, and arms.
Osler-Weber-Rendu syndrome = hereditary hemorrhagic telangiectasia
How are sugars attached to nitrogen-containing bases in nucleotides?
(between sugars-->hydrogen bonds; between nucleotides-->phosphodiester bonds)
Which step in collagen synthesis is impaired in pts with scruvy?
Hydroxylation of specific proline and lysine residues on the pro-alpha collagen
How does ethanol metabolism contriute to hypoglycemia?
increases NADH/NAD ratio in liver --> so, causes:
***So, inhibits gluconeogenesis and stimulates hepatic fatty change
***So, get overproduction of lactate-->acidosis; also overproduction of NADPH-->increased fatty acid synthesis