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38 Cards in this Set
- Front
- Back
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What are the roles of adenylyl cyclase and phosphodiesterase on cAMP?
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adenylyl cyclase uses an ATP to make more cAMP. It is stimulated by NE, epi, beta agonists, ACTH, TSH, glucagon, GH. It is inhibited by ACh on M2/M4, Alpha 2 agonists, PGE, Insulin, niacin, adenosine
PDE - breaks down cAMP. It is stimulated by insulin. Inhibited by Thyroid hormone and methylxanthines (stims adenylyl indirectly) |
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What is acetyl CoA in the liver as opposed to in the mitochondrial matrix?
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in the mitochondria it is put into the TCA cycle to make ATP and CO2. when this cycle is oversaturated it is made into a ketone body
in the liver - can be made into cholesterol by way of HMG CoA reductase) or can be made into Malonyl CoA. This then makes Palmitate (major FFA) or inhibits the action of Acyl CoA going into the mitochondria (decreasing ATP from acetyl CoA) |
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What is Palmitate? Where does it come from?
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fatty acid - is the sole fatty acid from which all other fatty acids are manufactured
Fatty acid synthase catalyzes the connection of one acetyl CoA molecule to 7 malonyl CoA molecules, causing the fatty acid chain to grow by 2 carbons for each malonyl CoA added; the product is palmitate (16 carbon) |
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What is the MOA for thin body habitus in type 1 diabetics?
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are not ale to manufacture insulin. Lack of insulin results in decreased actyl CoA carboxylase activity. Less fatty acids and fewer triglycerides are made
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What is the process for DKA?
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high rate of fatty acid oxidation results in ketogenesis
combination of lack of insulin and too much epi allows for excessive hormone sensitive lipase activity - resulting in excessive triglyceride metabolism and fatty acid oxidation. TCA becomes saturated with acetyl CoA - allowing excess acetyl CoA to be metabolized to ketone bodies - resulting in DKA |
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What results from carnitine deficiency?
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seen in premies and hemodialysis pts
low carnitine palmitoyl transferases levels are low - leading to decreased fatty acid oxidation ketone bodies are never made - raising plasma FFA because they are not metabolized properly The plasma FFAs cause hypoglycemia due to decreased gluconeognesis |
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What are the roles of Prostaglandins? Thromboxanes? Leukotrienes?
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P - vasodilation, exudation, and pain
T - platelet aggregation and vasoconstriction L - POTENT bronchoconstriction |
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What are the different types of fatty acids?
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mono-unsaturated (one C=C double bond) - palmitoleic acid, Oleic acid
Poly-unsaturated (several C=C double bonds) - linoleic acid, linolenic acid, arachidonic acid saturated (no C=C double bonds) - palmitic acid, stearic acid |
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What is the rate limiting step of cholesterol synthesis? what activates it? inhibits? What drugs act here?
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HMG-CoA reductase
active - insulin inhibited - glucagon, glucocorticoids, and cholesterol HMG-CoA reductase inhibitors (statins) are drugs that work here |
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What are the 2 ways the sterol ring are eliminated?
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conversion to bile acids which are excreted in feces
secretion of cholesterol into bile which is eliminated to feces |
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What are xanthomas?
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accumulation of cholesterol-laden macrophages in various body structures
includes tendons, skin and other locations |
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What are the most abundant phospholipids in human eukaryotes? which one is the primary component of surfactant?
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phophatidyl choline (surfactant) and phophatidyl ethanolamine
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what makes up glycolipids? gangliosides?
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glyco - ceramide + sugar(s)
gang - ceramide + oligosaccharide + N-acetylneuraminic acid |
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What is a cerebroside?
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type of glycolipid
ceremide + sugar |
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What are sphingolipids?
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make up (with FAs) the bulk of the myelin sheath that insulates nerve fibers of CNS
sphingolipidoses are very destructive to CNS |
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What are sphingolipidoses?
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disorders marked by an inability to metabolize or degrade certain shpingolipids, resulting in accumulation of certain sphingolipids.
It is a result of dysfunction of cellular lysosomes Fabry is only one that doesn't result in CNS disorder |
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How can you tell the difference between Nieman-Pick and Tay-Sachs
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NP - hepatosplenomegaly, MR, cherry red macula, fatal
TS - no hepatosplenomegaly, cherry red macula, blindness, Ashkenazi Jews |
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What is the role of pepsinogen?
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breaks down dietary protein into various sized peptides and free amino acids
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What is the process that Phenylalanine makes NE/Epi?
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Phenylalanine - tyrosine (by THP and phenylalanine hydroxylase) - DOPA - dopamine (by decarboxylation) - NE (by hydroxylation by a VIt C dependent pathway) - epi
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What is it that makes us sleepy after eating tryptophan?
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melatonin in the pineal gland
Tryptophan - 5-HT (by THP) - sertonin (by decarboxylation) - melatonin (adding an acetyl CoA) |
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What is the difference between glutamate and GABA?
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glutamate - stimulatory neurotransmitter
GABA - inhibitory neurotransmitter |
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What are the major products made during the process of making hemoglobin from glycine?
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porphyrinogens
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What is the role of homocysteine? problem with having too much?
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stims blood vessel inflammation of endothelium
increases artherosclerosis, MR, lens dislocation, traps adenosine as SAH - MR |
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What causes phenylketonuria? what are the symptoms?
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phenylalanine hydroylase deficiency OR defect in THP production
phenyl ketones accumulate - resulting decreased DOPA, epi, NE production musty odor of urine, hypopigmentation, MR tx: Phe-free diet |
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What causes Maple Syrup disease? What are the symptoms
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AR
alpha-ketoacid dehydrogenase deficiency - accumulation of branched chain amino acid (isoleucine, leucine, valine) urine smells like maple syrup or burnt sugar evident by week 1 - extensive brain damage - MR dx: enzyme assay at birth Tx: prior to 1 wk - dietary proteins free of BCAA highest incidence in world is Old Order Mennonites of Lancaster and Lebanon Co, PA |
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What causes Cystinuria?
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defect in membrane transport of dibasic amino acids (cysteine, ornithine, arginine, and lysine) - impairing renal reabsoprtion of these
high cysteine is oxidized to cystine, resulting in urolithiasis - cystine urolithiasis (black stone) looks like COAL |
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What must happen to all 6-carbon sugars before they can be utilized in any metabolic pathway?
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phosphorylated (a phosphate group added)
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What are the differences in hexokinase and glucokinase?
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hexo - most tissue, increased affinity for glucose, low capacity, has negative feedback by G6P, ensures a supply of glucose for tissues, as well as avail other hexoses to cells
gluco - mainly in liver, b-islet cells, glucose only and must be at very high concentrations, not inhibited by G6P, removes glucose from blood following a meal |
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What results from an aldolase B defect?
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fructose intolerance - accumulates fructose1PO4 and fructose 1,6PO4 - builds up in kidney and liver resulting in kidney/renal failure
also a problem in glycolysis - glycogenolysis and gluconeogenesis are shut down - dangerous hypoglycemia in between meals |
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What is the problem in lactose intolerance?
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can't digest lactose because lactase defect - increased lactose within intestinal lumen
tx: lactose free diet or lactase tablets with dairy ingestion flatus, bloating, borborygmi, diarrhea |
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What happens with galactosuira?
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defect in galactose-1-PO4 uridylyl transferase
results in accumulation of galactose 1 P and build-up of galactose AR increased serum galactose MR, physical shunting galactose 1P depletes liver of PO4, resulting in liver failure within a few weeks after birth and being fed milk - anorexic, vomits, stops growing, icteric cataracts occur in fetus in utero |
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What are powerful stimulators and inhibitiors of glycogen synthase?
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glycogen synthase is rate limiting step in glycogen synthesis
+ = G6P - = cAMP cAMP is stim by glucagon and epi. it is inhibitied by insulin |
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What is the defect in Von Gierke disease?
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lack of G6P phosphatase
accumulates G6P and G1P G6P major product of gluconeogenesis - because of lack of G6P, it cannot become glucose via gluconeogenesis - instead it glycogenesis even if they are hypoglycemic glycogenolysis will not occur, further exacerbating hypoglycemia results in hepatomegaly and enlarged kidneys secondary to glycogen deposits and hypoglycemia |
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What is McArdle's disease?
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skeletal muscle phosphorylase deficiency - accumulation of glycogen in skeletal muscle - can't break down glycogen for energy when needed
when glycogen is needed (exercise), muscle pain and cramps occur with no rise in lactate - muscles are starved for glucose for glycolysis progressive muscle weakness, despite muscles having increased glycogen content |
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What are mucopolysaccharidoses?
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diseases marked by an inability to metbolize or degrade certain mucopolysacharieds.
results in the accumulation of excess amounts of certain mucopolysaccharides. - due to dysfunction of lysosomes (cellular component responsible for turn-over and degradation of mucopolysaccharides) |
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What is the difference between Hurler, Scheie, and Hunter?
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defect:
Hurler - alpha L iduronidase Scheie - alpha L iduronidase but different mutation Hunter: iduronate sulfatase symptoms: hurler - corneal clouding, MR Scheie - corneal clouding, NML intelligence Hunter - NO corneal clouding, MR |
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What are porphyrias? What is the most common?
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defects in heme biosynthesis - all are AD (except erythropoietic and acquired - AR)
MC - cutanea tarda - build up of uroporphyrinogen 3 |
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What are the symptoms of porphyrias?
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(+) photosensitivity
microcytic anemia abdominal pain oxidative damage to multiple tissues secondary to oxidation of the excess heme precursors - severe cosmetic and functional deformities |
