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93 Cards in this Set
- Front
- Back
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What are the components of the pyruvate dehydrogenase complex?
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TPP: Thymine pyrophosphate
Lipoic acid Coenzyme A FAD (from riboflavin) NAD+ (from niacin) |
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What are the two ketogenic amino acids?
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Leucine
Lysine |
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Describe the Cori cycle
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Lactate from RCB and skeletal muscle is sent to the liver to be converted into glucose. Then glucose is returned to the RBC and skeletal muscles.
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Pyruvate metabolism is under controlled of which 4 enzymes?
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Lactate dehydrogenase (Anaerobic tissue): Pyruvate <---> Lactate [NADH to NAD+].
Alanine aminotransferase (ALT, GPT, Muscle): Pyruvate <---> Alanine Pyruvate Carboxylase: Pyruvate ---> Oxaloacetate ---> TCA or Gluconeogenesis Pyruvate Dehydrogenase: Pyruvate--->Acetyl-Coa--->CO2+H2O (TCA) or Fatty Acid synth. |
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What's the MoA of the treatment for cyanide poisoning?
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Nitrites to form methemoglobin which binds cyanide
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What's the rate-limiting step of the TCA cycle?
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Isocitrate dehydrogenase:
Isocitrate ---> alpha-Ketoglutarate + NADH + CO2 |
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What's the MoD of Leber Hereditary Optic Neuropathy (LHON)?
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Mutations of complex I and III of the ETC --->
Impairment of ATP production by oxidative phosphorylation ---> Accumulation of NADH inhibits pyruvate dehydrogenase ---> Lactic acidosis. |
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What are the irriversible enzymes of glycolysis?
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1) Hexokinase/Glucokinase
2) Phosphofructokinase 1 3) Pyruvate Kinase |
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The four key enzymes of gluconeogenesis
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1) Pyruvate Carboxylase: Pyruvate ---> Oxaloacetate
2) Phosphoenolpyruvate Carboxykinase: Oxaloacetate ---> Phophoenolpyruvate 3) Fructose-1,6-Bisphosphatase: Fructose-1,6-Bisphosphate + H2O ---> Fructose-6-Phosphate + Pi 4) Glucose-6-Phosphatase: Glucose-6-Phosphate + H2O ---> Glucose + Pi |
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What are the precursors of gluconeogenesis?
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Lactate (cori cycle)
Alanine (transamination of pyruvate) Glucogenic Amino Acids (all except lysine and leucine can be converted into TCA and glycolysis intermediates) Odd-numbered fatty acids Fructose Galactose |
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Glycogen storage diseases and their enzyme deficiencies
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Type I: von Gierke; Glucose-6-Phosphatase
Type II: Pompe; alpha-1,4-Glucosidase Type III: Cori; Glycogen Branching Type IV: Andersen (amylopectinosis); Branching enzyme Type V: McArdle; Muscle glycogen phosphorylase Type VI: Hers disease; Hepatic glycogen phosphorylase Type VII: Muscle phosphofructokinase Type VIII: Hepatic phosphorylase kinase |
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What's the mechanism of treatment of hyperkalemia with insulin and glucose?
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Influx of K+ into the cell is coupled with the entry of insulin and glucose.
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Alanine cycle steps
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Muscle: glucose ---> pyruvate ---> alanine
Liver: Alanine ---> pyruvate (---> glucose) + NH2 ( + 4 ATP ---> Urea) |
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What is the function of the hexose monophosphate shunt?
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An alternative route for the oxidation of glucose which supplies the cells with NADPH and pentoses.
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What are the functions of NADPH?
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1)Synthesis of fatty acids and steroids
2)Maintains the reduced form of glutathione which prevents hemolysis (Protects against ROS) 3) Bactericidal activity in PMNs and macrophages by generating superoxides. |
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What's the MoD of chronic granulomatous disease?
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Neutrophils cannot produce superoxides due to a defect in the NADPH oxidase complex.
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Which enzyme mediates the rate limiting step of the HMP shunt?
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Glucose-6-Phosphate Dehydrogenase
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What's the MoD of glucose-6-dehydrogenase deficiency?
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In G6PD there is a decrease production of NADPH ---> decrease in the reduced form of glutathione ---> Increase in superoxide and hydrogen peroxide ---> Hemolysis
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Which drugs exarcerbate the hemolysis in G6PD?
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Aspirin, antimalarials, antituberculous, and sulfonamides
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What are the major classes of lipids?
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Fatty acids
Triacylglycerols Ketone bodies Cholesterol Phospholipids Sphingolipids |
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Arachidonic acid is the major precursor of which compounds?
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Thromboxane
Prostaglandins Leukotrienes |
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Which lipid deficiency in the premature newborn gives rise to respiratory distress syndrome?
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Dipalmitoylphosphatidylcholine;
It is the active component of surfanctant which forms a film that lines the alveoli and reduces surface tension. |
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Key enzymes of fatty acid synthesis
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Acetyl-CoA Carboxylase:
First step/Rate-limiting step Acetyl-Coa + HCO3 + ATP ---> Malonyl-Coa + ADP + Pi Fatty acid synthase: Lengthens fatty acid chain by 2 carbons |
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Location of fatty acid synthesis/fatty acid oxidation
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Fatty acid synthesis: Cytosol
Fatty acid oxidation: Mitochondria |
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What enzyme is responsible of converting fatty acids to fatty acyl-CoA?
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Fatty acyl-CoA synthetase (thiolase)
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Which shuttle is responsible for bringing fatty acids into the mitochondria and what enzyme is responsible for the rate-limiting step?
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The carnitine shuttle uses carnitine-acyl transferase I
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Which vitamin is essential for carbohydrate metabolism?
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Thiamine (vitamin B1) is converted to thiamine pyrophosphate.
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Which vitamin is essential for amino acid metabolism?
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Vitamin B6, pyridoxal phosphate
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Biotin is important is the synthesis of?
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Fatty acid synthesis
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What are the 3 components of the PDH complex?
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1) Pyruvate dehydrogenase (decarboxylase)
2) Dihydrolipoamide transacetylase 3) Dihydrolipoamide dehydrogenase |
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What metal is needed for the function of thiamine pyrophosphate?
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Magnesium
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What disease is associated with sphingomyelinase deficiency?
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Niemann-Pick disease
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What is the process of lyonization?
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Random inactivation of an x chromosome in each cell.
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What's manifesting heterozygote?
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When the active X chromosome is the one with the mutant gene.
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Why do autosomal domininant diseases manifest?
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1) More than 50% of the normal gene product is needed for a nondiseased state.
or 2)The defective protein has acquired a novel detrimental property. Structural proteins and membrane receptors are usually affected |
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What is southern blotting?
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Used to detect DNA
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What is northern blotting?
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Used to detect RNA
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What is western blotting used for?
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Used to detect protein
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What's allelic heterogeneity?
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Different mutation on the same allele
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What's compound heterogeneity?
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When the same exact locus is not mutated on each copy
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What's the equation used to describe the phenotypic distribution of a disorder and the genotypic distribution of an abnormal allele?
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Hardy-Weinberg
1 = p2 + 2pq + q2 1 = p + q p2 = unaffected 2pq = carriers q2 = affected q = frequency of normal allele q = frequency of abnormal allele (1 - p) |
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Tay-Sachs
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Tay-Sachs:
1: Autosomal recessive 2: Lysosomal storage disorder 3: Hexosaminidase A deficiency 4: Accumulation of cerebral ganglioside (GM2, a sphingolipid) 5: Cherry red spot on macula |
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Describe the Hurler and Hunter syndromes
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Coarse facial features, mental retardation
Hurler syndrome: Alpha-1-iduronidase deficiency Autosomal recessive Hunter syndrome: Iduronate sulfatase deficiency X-Linked recessive |
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Glucocerebrosidase deficiency
Hepatosplenomegaly |
Gaucher's disease
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Sphyngomyelinase deficiency
Neurological dysfunction |
Niemann-Pick disease
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2 year old
Choreoathetosis Spasticity Self mutilation Orange "sand" in the diapers |
Lesch-Nyhan syndrome
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HPRT deficiency
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Lesch-Nyhan syndrome
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Which enzyme does allopurinol inhibit?
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Xanthine oxidase
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Which bonds are destroyed when DNA is denatured?
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Hydrogen bonds.
No covalent bonds are broken. |
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Which methods are used to denature DNA?
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Heat
Alkaline pH Chemicals (formamide, urea) |
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What is the hyperchromic effect?
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The increase in absorbance of a DNA solution at a wavelength of 260nm in the DNA melting curve.
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What is the melting temperature (Tm) of denaturing DNA?
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It is the temperature at which the DNA is half denatured (half of the hydrogen bonds are broken)
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Which one G-C or T-A will have a higher Tm?
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G-C bonds because they have 3 hydrogen bonds
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DNA A protein function
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It recognizes origin of replication in bacterial DNA
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Helicase function
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Denatures DNA
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Single stranded DNA binding protein (SSB)
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Prevent the strands from reassociating and protects them from degradation by nucleases
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Primase
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Synthesizes a short RNA primer (5'--->3')
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DNA pol III
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Begins synthesizing DNA in the 5'--->3' direction beginning at the 3' end of each primer (leading strand)
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DNA pol I
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Fills the gaps and removes RNA primers
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DNA ligase
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Seals the nicks between Okazaki fragments (requires NAD/ATP)
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DNA pol delta
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Synthesizes the leading strand during replication
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DNA pol alpha
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Synthesizes the lagging strand during replication
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DNA pol beta and epsilon
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DNA repair/DNA pol e may substitute for DNA pol d
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Topoisomerase II
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Removal of positive supercoils ahead of advancing replication forks
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Telomerase
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Finishes 5' end
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Reverse transcriptase
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RNA-dependent DNA pol
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What are the essential amino acids?
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PriVaTe TIM HALL
Phe, Val, Thr, Trp, Ile, Met, His, Arg, Leu, Lys |
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Glycogen storage: Anderson's (IV) vs. Cori's (III) enzyme defect
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defect ABCD: Anderson's=Branching enzyme Cori's=Debranching enzyme
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Pompe's disease
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"Police = Po + lys": Pompe's disease is a lysosomal storage disease (alpha 1,4 glucosidase).
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Metabolic acidosis (normal anion-gap) causes:
1) Hyperkalemia 2) Hypokalemia |
With Hyperkalemia:
RAISE K+: RTA type 4 Aldosterone or mineralocorticord deficiency Iatrogenic: NH4Cl, HCl "Stenosis": obstructive uropathy Early uremia With hypokalemia: ReDUCE K+: Renal TA type 1 and 2 Diarrhoea Urine diversion into gut Carbonate anhydrase inhibitor Ex-hyperventilation |
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Enzyme kinetics:
competitive vs. non-competitive inhibition |
With Kompetitive inhibition: km increases; no change in Vmax. With Non-kompetitive inhibition: No change in km; Vmax decreases.
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Hemoglobin binding curve: causes of shift to right
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"CADET, face right!":
C = Increase in carbon dioxide, A = Acidosis (low ph), D = Increase in 2,3 DPG aka 2,3 BPG, E = Exercise, T = increase in temperature |
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Adrenaline mechanism
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"ABC of Adrenaline": Adrenaline--> activates Beta receptors--> increases Cyclic AMP
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Carbon monoxide poisoning electron transport chain target
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"CO blocks CO":
Carbon monoxide (CO) blocks Cytochrome Oxidase (CO) |
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Glycolysis steps
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"Goodness Gracious, Father Franklin Did Go By Picking Pumpkins (to) Prepare Pies": Glucose Glucose-6-P Fructose-6-P Fructose-1,6-diP Dihydroxyacetone-P Glyceraldehyde-P 1,3-Biphosphoglycerate 3-Phosphoglycerate 2-Phosphoglycerate (to) Phosphoenolpyruvate [PEP] Pyruvate • 'Did', 'By' and 'Pies' tell you the first part of those three: di-, bi-, and py-. • 'PrEPare' tells location of PEP in the process.
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Glycolysis Enzymes Mnemonic
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“Hungry Peter Pan And The Growling Pink Panther Eat Pies.”
Hexokinase Phosphohexo Isomerase Phosphofructokinase-1 (6-phosphofructo-1 kinase) Aldolase Triose phosphate isomerase Glyceraldehyde 3-phosphate dehydrogenase Phosphoglycerate kinase Phosphoglycerate mutase Enolase Pyruvate kinase |
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Citric acid cycle compounds
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"Our City Is Kept Safe And Sound From Malice": Oxaloacetate, Citrate, Isocitrate, alpha-Ketoglutarate, Succinyl-CoA, Succinate, Fumarate, Malate
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Citrate Cycle Enzymes Mnemonic
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"Corrupt Anti Intelligence Agent Spoke Slander For Money." Citrate synthatase, aconitase, Isocitrate dehydrogenase, Alpha ketogluturate dehydrogenase, Succinyl CoA synthetase, Succinate dehydrogenase, Fumarase, Malate Dehydrogenase
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B vitamin names
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"The Rhythm Nearly Proved Contagious": • In increasing order: Thiamine (B1) Riboflavin (B2) Niacin (B3) Pyridoxine (B6) Cobalamin (B12)
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Electron transport chain: Rotenone's site of action
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Rotenone is a site specific inhibitor of complex one
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Golgi complex: functions
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"Golgi Distributes A SPAM": Distributes proteins and lipids from ER Add mannose onto specific lysosome proteins Sulfation of sugars and slected tyrosine Proteoglycan assembly Add O-oligosugars to serine and threnonine Modify N-ologosugars on asparagine
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Pyruvate: products of complete oxidation
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"4 Naked Fun 3 Coeds + 1 Guy": • Complete oxidation of pyruvate yields: 4 NADH FADH2 3 CO2 1 GTP
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Catabolism steps of branched chain amino acids
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"Truck hit the Ox to Death": Transamination Oxidative decarboxylation Dehydrogenation
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Niacin deficiency: signs and symptoms
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4 D's: Diarrhoea Dermatitis Dementia Death (if untreated)
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Enzymes: classification
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"Over The HILL": Oxidoreductases Transferases Hydrolases Isomerases Ligases Lyases • Enzymes get reaction over the hill.
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Phenylketonuria (PKU): which enzyme is deficient PHenylketonuria
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Phenylalanine Hydroxylase
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cDNA libraries
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complementary DNA libraries are made by reverse transcribing (making DNA from RNA) all of the mRNA in a cell. The DNA copies are replicas of mRNA without introns. These can be used as probes, primers, or many other uses.
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Transcription factors
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Bind to promoters, and help recruit RNA Polymerase II, which binds the TATA box and CAAT box, located upstream
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Enhancer regions
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Bind specific protein that aid in transcription of certain genes. These regions can be located upstream, within the gene, within introns, close, or far from the transcription start site.
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MoA of steroid hormones
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Steroid hormones cross membranes and travel directly to the nucleus of target cells. Bound to their respective receptors, steroid hormones act like transcription factors or enhancer binding proteins. They bind to hormone response elements near the genes they regulate and either enhance or inhibit transcription of those genes.
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What's the pKa of histidine?
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6 does not ionize at physiologic pH
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The role of SH2 domains
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They are normally found in proteins involved in signal transduction. By binding to phosphotyrosine, they allow signals to be passed from one molecule to another. For instance
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Inherited hyperlipidemias-- Type Increased lipoprotein
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I Chylomicrons Triglycerides
IIa LDL Cholesterol IIb LDL and VLDL Cholesterol and triglycerides III Remnants Triglycerides and cholesterol IV VLDL Triglycerides V VLDL and chylomicrons Triglycerides and cholesterol |
